Sherlock glanced at John, who nodded almost imperceptibly. Sherlock's finger ghosted the trigger of the gun as John tensed his muscles.
He fired.
In the second before Sherlock pulled the trigger, John jumped forward, using all the power in his legs to propel him. He sighed an apology into Sherlock's ear, for more than one reason, and then his body slammed into the taller, leaner one of Sherlock. Sherlock went flying into the pool with a splash. He sunk to the bottom, unconscious.
Meanwhile, John had crashed into the floor, with a sickening crunch as his leg crumpled beneath him, just falling short of the pool. He felt all hope leave him; not falling into the pool meant he WOULD die. He thought of Sherlock, and the bomb exploded.

Flames and shrapnel engulfed the army doctor. The blast threw him into the air and across into the pool, and then he too sunk to the bottom.

Sherlock's eyes snapped open. He immediately took in his surroundings. His eyes narrowed partly because they were stinging in the chlorine, partly because he, Sherlock Holmes, recreational drug user, never passed out by any other means than drugs. Suddenly, his well trained body began to protest for oxygen. He used his hand to push against the pool floor, up to the surface. It seemed an age before he broke the surface, coughing and spluttering. He swam slowly, in weak strokes, to the side of the pool and pulled himself out. He lay on the side, taking in his surroundings; processing the data. It had been a bomb, as Sherlock had known from the beginning. The walls were engulfed in flames, and falling down, there were bits of cubicle and wall strewn everywhere. He scanned the room for Moriarty, but there was no sign of him. He snarled weakly. How had he escaped unharmed? It was impossible. Sherlock looked at all the exits and he knew Moriarty wouldn't have, couldn't have escaped, there was no way he could run faster than a bomb. So, unless he was wearing very thick protective armour, he had been hit, and hurt.

A weak cough reached Sherlock's ears. It was quite high pitched, therefore it could only be Moriarty. Sherlock felt a pang of worry for John, but he buried that, John was a soldier, he would be fine. He hauled himself to his feet, staggering slightly, and spitting out water from his lungs. Sherlock carefully mapped out the safest route to the noise and stepped over the rubble, avoiding the flames and puddles of water. He reached the last remaining cubicle; it was in bad shape, only the bottom half remained. He looked inside, and Moriarty lay there, crushed by the viewing gallery that fell from above on him in his 'safe' area. Sherlock stalked inside.

"No please, Sherlock, have mercy!" Moriarty wheedled, as he grinned apologetically at him.
"Looks like I won." Sherlock hissed, stepping next to the man, and bending down next to his head. He grabbed the man's neck and was on the verge of breaking it, when the other man began to speak.
"John's...dead." Moriarty coughed out. Sherlock sneered. His attempts to win were pathetic. He'd lost to Sherlock; a smarter man. Then he looked into Moriarty's eyes, and they were shining and clear. He was telling the truth. Sherlock recoiled slightly. Moriarty noticed and began to laugh deeply. Maybe he had won after all. Sherlock gazed at him and snapped his neck. He kicked his body to the ground and stood up. He stalked to the edge of the pool. "JOHN!" Sherlock roared. "JOHN WATSON!" He looked around, searching for John's body, trying to spy if it stuck out from under any rubble. "Oh." He murmured as he looked down into the pool. There, at the bottom of the pool, in amongst the rubble, lay Sherlock's heart.

Sherlock shivered despite the fires still raging around him. He straightened up, and dove in gracefully, pushing debris out of the way. He reached the bottom in a few powerful strokes and pulled John to his chest. John's blood was dying the pool a mocking crimson. Sherlock growled internally, he should have noticed before, instead of wasting time on Moriarty. Sherlock planted his feet on the pool floor, and pushed with John locked tightly in his arms. Sherlock rushed upwards, their heads breaking the surface. Sherlock sucked in a breath and swam to the side, John's weight dragging him down immensely. His anger caused him to not notice, and he quickly reached the side and pushed John's body out of the water. He heaved himself out and fell to his knees next to his friend.

He checked the man's pulse in several places; wrist and neck, but no blood ran through, it was as still as the grave. Sherlock then noticed the gaping hole in John's torso. It was a messy slice, but large, it had taken a few organs with it. He reasoned that a piece of shrapnel had caused the damage. "At least it was instant."
Sherlock pulled the body of his only friend to him and hugged it. For the first time in his life, the consulting detective cried. A single tear fell onto John's face. He knew that John had given his life to save Sherlock. Sherlock felt bitter. He felt as though he was living on borrowed time. John should have been alive. He was the good man, the kind one. Sherlock pressed his face to John's neck.

"Sherlock! Doctor Watson!" Lestrade's voice rung out. He knew Mycroft would have sent him; he would have been watching John all the time. Sherlock looked up dimly. Too late brother, he thought angrily. Lestrade came running into the vicinity and saw the pair. A group of firemen were close behind, with fire hoses and shovels. Lestrade beamed as he came over. "You're OK!" Sherlock snorted at his words, and then realised that at the angle they were bent, John's injuries were hidden. Lestrade frowned slightly at Sherlock's position but said nothing. "So, what happened this time?"
"Our criminal mastermind is dead." Sherlock waved a hand vaguely in the direction of Moriarty. Lestrade smiled a tight lipped smile. Then Sherlock dropped John's body.
"Oh God!" Lestrade exclaimed, jumping away. He saw pain in the younger man's eyes. "Is he...?" The question hung in the air. "Of course!" Sherlock snapped. "The shrapnel tore through his heart, lungs and upper intestines in an instant. There's also a tiny bit embedded at the base of his neck. Instantly dead." Sherlock looked up, lost. "He gave his life for me."

The next hour passed without Sherlock noticing. His attenion was diverted elsewhere; he was running all the different scenarios of that final conflict through his mind, considering all the different ways it could have gone. Suddenly, he felt a tender hand on his arm, and he snapped back to the present. Lestrade stood next to him, his expression soft. Sherlock ripped his arm away, and then jumped out of the hospital bed. Lestrade kept his face neutral, but even coming from the cold detective, that hurt. Sherlock felt a vague itch as the needle pulled out from his hand, and the cuts and bruises that littered his body ached.
"Sherlock, wait, what are you doing? You need to stay in hospital to heal!" Lestrade cried. Sherlock gazed levelly at him. He realised his clothes had been changed and he was in a pristine suit; his brother no doubt.

"Detective Inspector, I am fine. Now if you'll excuse me, I need a cigrarette." Sherlock dashed to the door of his room, wrenched it open, and ran down the corridors. He noted all the signs and quickly found an exit. His hands slipped inside his pocket, touching his BlackBerry reassuringly – wait! He pulled it out disgustedly. It wasn't his. The corners were sharp, unlike his own, which had been worn down by his incessant texting. Sherlock sighed, at least he had a working phone. He pulled loose change from the pocket as he exited Charing Cross Hospital. The air was sharp and old around him, pulling him to his senses. He judged the moving cars and ran across blindly. Cars beeped at him as he barely escaped with his life. He ran a few hundred metres down the road and entered a corner shop. He walked up to the young Asian man behind the desk. "A ten pack of Marlboro and a lighter." He said tersely. The man gave it to him without speaking. He was used to the rude banker types and junkies that usually came in. Sherlock threw a twenty pound note at the counter and skulked out. He stopped, visualised the area in his head, and slipped off towards the right.

He had been walked for a minute, when he reached a dark alleyway. He slipped down it, pulled out a cigarette, put it in his mouth, flicked his lighter on with his thumb and lit it. He put the lighter inside his trouser pocket and then took a long drag, sinking to the floor. He'd have to chain smoke the pack, he was shaking badly and needed a release. He took another drag, and looked upwards at the stars shining brightly. His mind slipped back to John.
"Beautiful, isn't it?" His own voice broke the silence between him and John. He saw John glance at him, in an almost adoring fashion and smile. "I thought you didn't-"
"Doesn't mean I can't appreciate it" came his own gentle retort.

His eyes snapped open. His cigarette had burnt itself halfway down to the butt. Sherlock finished it off, inhaling sharply and swallowing the smoke and then flicked the butt away. He sighed shakily and pulled out his phone. He texted a number that was not saved on this sim card:
Your strongest drug now. The alley next to Pizza Place, Charing Cross Road. SH.
He knew his brother would be able to trace him through this phone. He had expected to see Mycroft already. Maybe his brother did understand him and his needs. Slightly. Sherlock glared out at the darkness, waiting for his release to come.

The shady drug dealer had slipped away. Sherlock moaned aloud as his ripped the syringe from its brown envelope. The syringe contained an odd, gloopy blue liquid. Sherlock held it up to the moonlight, in a gesture reminiscent of his first case with John. A slow smile spread across his face as he knew this drug would release him from this torture for a while. Sherlock unbuttoned the cuff of his left sleeve and hastily pulled it up, just above his elbow. He lined the needle up with the veins in his elbow and inserted it with a stifled sigh. He pushed on the plunger and the liquid roared into his veins. As unreceptive as he was, he felt its effective immediately. It was a powerful drug. His head lolled to the side and he smiled. Suddenly, swimming before his conscious, was John, looking very disapprovingly at him.

"Just because I'm gone doesn't mean you need to resort to this. Find a case." John whispered.

"YES IT DOES!" Sherlock screamed into the night. "YOU LEFT ME! I didn't want your life in return for mine! I need to forget you. Forget the pain! Forget..." His eyes flickered and John was gone. "Come back..." He choked out. He focused his gaze for a second and let out a strangled moan. The only man keeping him tethered to this world, his only friend was gone. Sherlock let the drugs wash over him and he passed out, falling onto his injected arm, as he fell into an unconscious bliss.