Inspired by the missing scenes from His Last Vow, and in particular by how John might have reacted to the sequence of events that unfolded.

Rated M for language and some of the more gorey medical details. Probably not a story for the squeamish! I've also gone for medical accuracy over the finer details in the episode on the rare occasions that I couldn't make the two coincide (Sherlock's teeny, tiny thoracostomy scar after emergency thoracic surgery, for example).

As ever, please do let me know what you think. Huge thanks to Sevenpercent and ThessalyMc for critiquing and inspiring x

John didn't hear the shot; silenced of course, the intruder must have been a professional after all. What he noticed instead was - complete silence. No footsteps, no sound, no voices. Where was Sherlock, and what could possibly be taking him this long?

Janine was awake now, sitting up, starting to talk sense, although he suspect she was mildly concussed. She kept on asking where Sherlock was, and what he was doing. John was asking himself the same question, but memories of Soo Lin, gunned down while he had run off to find her attacker, prevented him from leaving Janine to find out. A rustle from the other side of the room alerted him to the fact that the security guard, who looked like an even shadier character awake than he had unconscious, was awake too, and the next thing he knew, an alarm was sounded, and he was almost blinded by brightness as the lights came blazing on at full power. The security guard had obviously pushed his panic button. John should have thought of that, and taken his alarm away from him when he had checked him for breathing earlier. More company was the last thing that they needed.

''Tell him I'm one of the good guys, will you, Janine?' John said, as the security guard staggered to his feet.

'Ted, this is John. He's a friend of mine,' Janine said, rubbing her head, still sounding dazed. John had no idea what she'd been hit with, but she had quite a lump on her head already, quite enough to explain her semi-concussed state.

Ted grunted, although John suspected that this was more his normal level of conversation than a sequelae of his head injury. 'Shut off those alarms will you?' John hissed, 'if the intruder is still here, we don't want to make them bolt.' Janine reached for the phone and moments later, the alarms shut off as quickly as they'd started.

'Thank you,' John said, shaking his head in an attempt to stop his ears ringing. 'Now keep an eye on Janine will you?' he instructed the security guard as he ran towards the stairs, trying to remember which way Sherlock had gone. Up the stairs he knew, but there were two more floors above this one, so where was he? Think, John. All the doors on the first level up were closed, so he continued on up the next flight of stairs. A man with Magnussen's ego would accept nothing less than the penthouse for his office, he reasoned. Going with his instincts he carried on up. At the end of the corridor, a door stood ajar, a figure was slumped on the floor directly ahead. White shirt, light grey trousers, too stocky to be Sherlock. Magnussen? Had the intruder got to him too?

Cursing Sherlock for forbidding him from bringing his pistol, or even a tyre iron, John stationed himself behind the door, back to the wall, peering round it as quietly as he could to see who else was in the room. There was another figure lying on his back to the right of the door, in front of a large mirror. His head was turned away, but John recognised Sherlock instantly, and throwing caution aside, ran across to him.

He checked for breathing, then shook his friend, and when that failed to provoke a response, slapped his face lightly. There was no external evidence of head injury that he could see, but Magnussen was stirring now and clutching his head, so he could only assume that Sherlock had received the same treatment.

'What happened?' he asked Magnussen.

'Someone shot him,' came the calm reply. Trying to push aside the panic, John opened Sherlock's coat to reveal the red stain on the front of his shirt. Cold panic flooded through him, but he forced his brain into action. Right side of the chest, not the left. Thank fuck for that. But too close to the midline for his liking. Right ventricle, IVC, lung, pulmonary vessel, spinal cord. No, not that, please God, not that, anything but that. If he survived, but was paralysed, then how the hell would Sherlock cope with that?

He felt for a pulse with one hand - weak, thready, but palpable, while dialling 999 with the other. He could feel Magnussen watching him as he gave the details and the address to the call handler. Those cold, calculating eyes. Taking it all in, recording John's reaction for future use. What would his papers say tomorrow John wondered. Something about the love of John Watson for Sherlock Holmes? That would be all they needed - to have those old rumors reignited.

Odd how hard he was finding it to focus, to ignore Magnussen's enquiring glance, to focus on doing what he could for Sherlock. Should he move him? He was an army doctor, for fucks sake, and yet all of his training had deserted him under that reptilian stare.

'Go and let them in,' he snapped at the man, not attempting to conceal his contempt.

'I'm sorry?' this was obviously not a man used to receiving orders.

'The paramedics, go and let them in. They won't be able to get past your bloody security will they? Go and let them in.'

'And I should do that because?'

'Because if you don't, then I'll fucking kill you myself,' John hissed.

And something in his tone must have made Magnussen pay attention, because he left the room with a shrug.

Concentrate, John. Battlefield ATLS, drilled into him so many times. C comes first on the battlefield. Circulation, stop the bleeding. The external bleeding was a trickle only, although he had to rip Sherlock's shirt open to confirm that, the main bleeding would be internal he knew. Pressure on the wound might dislodge a bullet further, causing more damage, better to leave that alone. Sherlock's pulse was climbing, 140 now at the carotid, his radial pulse impalpable, blood pressure less than 70 systolic then. Fuck. He felt like howling in frustration, he had no kit, not even his GP bag. He would have cut off his own arm to give Sherlock his blood if he could have got it into him, but there was nothing that he could do.

Back to the beginning then - A for airway - patent, fast irregular breaths, with no signs of obstruction. That was something. B was for breathing, respiratory rate of forty, but both sides of the chest moving equally when he palpated it; so no pneumothorax - not yet anyway. Should he be putting something over the wound? Stop an open pneumothorax developing? The wound was small, less than two thirds of the diameter of the trachea was the old mantra wasn't it? He couldn't remember. What was wrong with him? Here he was, a doctor, and he was fucking useless. He started to shake as the adrenaline coursed through him. On the battlefield he would have known what to do. He would have had a role, he would have had a kit bag. An Asherman seal to put over the wound, two large bore cannulas and hang the fluid bags; get someone else to squeeze them, air evac the patient to base camp or better still to the ED at Camp Bastion where there would have been a full team waiting, and eight units of blood ready and waiting on the rapid infuser. Fuck, he hoped the receiving hospital would be ready for them. Where would they take him? The Royal London he hoped, best trauma centre in the city. If anyone could save Sherlock then they could.

He heard voices downstairs and footsteps coming towards them, crikey they had been fast. Sherlock was looking waxen now, sweat standing out on his forehead. Panicking slightly, John felt for his pulse. It was still there, but fainter and more rapid than ever. Then the paramedics were running into the room and his training clicked in.

He gave a rapid handover while an oxygen mask was applied, ripping open the cannula packet with his teeth and sliding the cannula into where he knew the vein should be, while the technician ran the fluid from the bag into the giving set; swearing slightly at the lack of flashback, then realising that the flashback was just painfully slow because Sherlock was so shut down. Attaching the fluid to the line, snapping at the paramedic that now wasn't the time for careful fluid administration in a patient who was close to exsanguinating. The first clot might be the best clot, but any fluid was better than arresting from hypovolemia. Pour it in, try to get his blood pressure to a level which would stop him from going into cardiac arrest, that was the priority now.

The paramedic looked at him and nodded at his snapped explanation. 'I served in Hellmand, and before that in Iraq. I'm not telling you how to do your job, but I've seen more gunshot wounds than you've had hot dinners, and I'm telling you that we've got about twenty minutes before this man arrests. So unless you want to crack a chest in the back of your ambulance, I suggest that we scoop and run. Now.'

And scoop and run they did. Onto the trolley, and running with Sherlock to the lift, strapping him in as they went, squeezing the bags of fluid as hard as they could during the seemingly endless trip down in the lift, then running with him into the ambulance, clicking the wheels of the trolley into the locks as the technician started the engine, and the sirens screamed into life as they pulled out into the traffic.

'Don't you fucking die on me, you bastard,' John murmured to his friend, as they weaved through the London streets, and he was thrown from one side of the ambulance to the other, being forced to brace himself with one arm against the side of the trolley. 'Don't you dare die on me, not again. I couldn't bear it. You hear me, Sherlock? You hold on.'

He pushed to the back of his mind the sickening realisation that if Sherlock's heart did stop, then he was the only one here who could do a resuscitative thoracotomy. Could he? Would he? They said that you never forgot. He'd only had to do one in his career as an army medic, out in the field. He'd witnessed others, but there had always been more experienced surgeons there to do the honors.

His one experience had been with a nineteen year old squaddie, out on his first tour, fresh out of training. He'd been shot by a sniper out on patrol, and John had been on the retrieval team who had gone out to get him. The boy had arrested in the helicopter ten minutes out from Camp Bastion, and John had done what he had been trained to do. Clamshell incision from the sternum spreading laterally both sides at the level of the fifth intercostal space, pair of trauma scissors to cut through the sternum, his hands shaking with effort, not with nerves. He had been doing what he was trained to do, what he had practised so many times on pig carcasses in the army training centre before he had been deployed. Through the sternum, suction out the blood - so much blood, how much blood could a human body hold? Pen torch held between his teeth, desperately trying to get a clear view, getting the medic in the helicopter cabin with him to hold the suction with one hand while starting internal compressions with the other, while he grabbed the scalpel, trying to hold it steady against the judder of the helicopter, seeing the hole, slicing through the surprisingly tough and fibrous pericardium to get rid of the blood surrounding the heart, finding the hole ripped through the left ventricle, knowing that he couldn't stop this, couldn't save this man, but not wanting to give up, not now. Continuing to squeeze the heart which took longer and longer to fill, watching the blood turn from dark red to rose as it was diluted by the fluid that they were pouring in. Watching the same fluid disappearing into the suction bag until it was full, switching to a second suction bag, and knowing that the majority of the five litres of blood that this man, this boy, had contained was now in that bag, and not where it needed to be.

He had continued squeezing that heart until they got him into the trauma bay of the ER, to the waiting trauma team; the blood on the rapid infuser, the waiting cardiothoracic surgeon. He had known that it was hopeless, but he had had to try none the less. The team had run for a full twenty minutes, while the cardiothoracic surgeon put in a temporary stitch to close the hole, while they poured ten, twenty, thirty units of blood into the boy, but he was dead. And nothing that they could do would bring him back.

It wasn't the worst injury that he had seen on his three operational tours as a frontline medic, but it was the one that had stayed with him the longest. That feeling of futility, of helplessness, was what had stopped him from pursuing a career in surgery. He didn't like being the last reserve, didn't like knowing that it was him or nothing. General practice suited him better. Even on that rare occasion when an emergency arose, there were usually colleagues around to back you up. And when there weren't, the paramedics were always eight minutes away or less. They had the detachment that John found that he now lacked. His own brush with death after his injury in Hellmand had left him with the odd feeling that the protective layer that he had built up over all those years had been stripped away, leaving his nerve endings exposed. He remembered being horrified as a student at the level of detachment displayed by those on the sharp end; at the black humor that enabled medical staff to laugh in the face of death. It was a defence, he had discovered. Because if you sat down and thought about all the horrors that you had seen, you would end up gibbering in the corner, and that didn't help you or the patient. Better to push it to one side, to crack inappropriate jokes, than to dwell on it.

He had lost that detachment though at some point in Afghanistan. Seeing half a platoon gunned down in front of him, running out to help before the all clear had been declared and receiving a parting shot from the retreating insurgents in his shoulder had made it all too close, too personal. Being wounded, becoming a patient, being certain in that moment that this was where he would breathe his last, out here in this dusty wasteland, was one thing. But what he had really struggled with, what had given him the flashbacks and the PTSD that had eventually invalided him out of the army, was the knowledge that he had let down those men. He had been the medic on that base station. Without him, the wounded men had had to wait until the helicopter retrieval team arrived for medical help. Without him three of them had died, and that was something that he would have to carry with him to the end of his days.

He had to focus now, concentrate on Sherlock, keep him alive until they reached The London. The monitor showed increasing number of ectopic beats, a sure sign of an irritated heart. A cardiac injury then, or perhaps just Sherlock's heart showing the effects of the blood loss. And then another thought crept through him. Icy cold realisation creeping in, as he turned Sherlock's head away from him, grabbed a pen torch from the paramedics pocket without asking, and shone it across Sherlock's neck. His jugular vein, the large vein in his neck, the one that should be flat from blood loss, was distended. That meant only one thing. Back pressure from the heart. He grabbed the stethoscope from where it was lying at the end of the trolley and listened for heart sounds. Quiet, muffled. Bollocks.

'Have you got a long needle?' he asked the paramedic sounding more calm than he felt?

'Only cannulas,' came the reply.

'So what do you do when your patient develops a cardiac tamponade?'

'Put our foot down,' came the grim reply, as the paramedic saw what he was seeing. 'Floor it, Mike, will you? We've got trouble back here.'

'Hold on Sherlock, just hold on,' John whispered, holding his friends hand, because he realised that doctor or not that was all he could do for Sherlock now. Hold his hand, and pray that they got there in time.