It was the explosion that woke him.

The sudden, all-enveloping, ear-shattering boom left every muscle in his body shaking and sweating, and it was immediately followed by deafening silence. The only thing he could hear was the incessant pounding of his heart thrumming in his ears.

Opening his eyes, he saw nothing. Then the shadows reformed themselves into the familiar pattern of curtains on the ceiling, courtesy of the streetlight outside his room. Small noises inserted themselves then, like the engine of a car passing by on the street, water running in the plumbing and, downstairs, the muffled sound of a radio.

His heart still beat like a sledgehammer, hard and fast as if it would in any moment break through his ribcage. He was sweating profusely and his throat was sore as if he had been screaming. Maybe he had, hopefully not. Swallowing hard, he forced himself to breathe slowly. Inhale through the nose, one two, and exhale through the mouth, one two. A shudder ran through his body, causing him to see again the images of the dream.

Memories, of course, half remembered and half forgotten. People, faces, and the rush of adrenalin coursing through his body before the blast – and then those same people dead, or worse. You did not need to be a doctor to know that some wounds could never be healed and that there was nothing you could do for those people other than beg to the powers that be for a swift delivery, and then pray for your own sake. Please God, let me live.

He opened his eyes again, having never consciously closed them, and knew that the pain in his shoulder was only an echo in the bone. Even so, it hurt like hell and staying in bed would do him no good. So he got up.

He made his bed out of habit rather than conscious decision or trying to procrastinate the moment when he would have to face the memories that had resurfaced. It was just the way it was: when you got out of bed, be it seven in the morning or, like now, two-thirteen in the dead of night, you made your bed. And then you- Well, that was the question. What did you do afterwards?

John almost sat down on the bed like he had done so many times before, when he remembered that there was actually an alternative. He was not confined to his room in any way, even if it was well past midnight. He could go downstairs, perhaps make a cup of tea. Yes, he would do that.

The first few steps were a pain. Just because he knew that the limp was psychosomatic did not mean that the pain went away. It did ease however, and with every step he felt a little bit better. That did not stop Sherlock from noticing it when he came into the kitchen though.

The consulting detective said nothing, he barely even looked up from whatever was on the petri dish under his microscope, but he did make a noise, somewhere between a snort, a huff and an almost pleased "I told you so"-sound. John decided not to give him the satisfaction of asking what the hell that was supposed to mean.

"Is there any tea?" he asked instead, even as he made his way to the kettle.

Sherlock hummed in what could be an affirmative response. John therefore found a cup and poured the tea into it, belatedly realising that the fluid that filled his cup was most definitely not tea.

"Sherlock!" he exclaimed, actually taking a step backwards "what is that?"

"Oh, don't worry, it's not poisonous."

"I wasn't asking if it was. What is, whatever it is, doing in the kettle?"

"It needed heating" the detective said simply, still absorbed by his findings in the microscopic world. "I'm done with it now though, just-"

Sherlock waved one hand dismissively, indicating that whatever happened to his concoction now, it was of no concern to him. John just sighed, put the contaminated cup and kettle in the surprisingly empty kitchen sink and took a new one from the cupboard. Microwave tea was not a favourite with him, but when the alternative was scrubbing the kettle free from the thick, greenish black substance currently in it…

"What are you doing?" he asked, rubbing his temples absently as he looked over the kitchen table covered in lab equipment and scribbled notes. Sherlock opened his mouth to answer, but John interrupted him.

"No, wait, don't tell me" he said, and then, when he saw the small fraction of hurt and disappointment in his friend's face, amended: "I'm sure it's interesting, but I don't think I could handle it right now."

The microwave beeped, an unnatural, blaring sound which John quickly moved to put an end to.

"You really should fire that therapist" Sherlock remarked. "Not only is she misdiagnosing you, she prescribes medicine that has no effect."

John grimaced - this was another discussion he was not too keen on having – and turned back to Sherlock, stirring the tea with a spoon, trying not to think about how the man had probably heard him thrashing about in bed just upstairs.

"They're meant to help you fall asleep, and they do that just fine." Whatever his mind was doing during sleep, he doubted there was any pill in the world that could remedy that.

He had not expected Sherlock to react to this, and was therefore surprised to see that he did. Then again, perhaps he had not, for he assumed his work again, adding some reagent or other to the petri dish and then sealed it before rising from his seat to put it in the fridge.

"Go sit down, John" Sherlock said casually, not quite but almost implying that John was somehow in the way. Seeing as standing in his pyjamas, in the kitchen, in the middle of the night, was not something John was very comfortable doing in the first place, he went to the living room instead and settled down in his usual armchair.

The radio was on, as he had heard from his room. Soft voices mumbled incoherently, partly, he realized, because they did not speak English, and he closed his hands around the steaming cup. From the kitchen he could hear Sherlock rustling about: opening and closing cupboards, the soft clinking of fine instruments against glass. Strange noises to find calming, but even so, he did.

A car honked violently out on the street and John sat straight up in his armchair, almost upsetting the teacup before regaining his composure. He shuddered involuntarily as he put the cup down on the small coffee table, mentally berating himself for his raw nerves even though he knew that there was really very little he could do about it. As he tried again to breathe normally, he heard the scraping sound of Sherlock's chair in the kitchen and then the man's steps against the floor and the buzz of the radio switched off.

"Your presence is like a lighthouse" the younger man commented as he flung himself down in his own chair and reached for the violin. "Good for boats, I imagine, but Copernicus would have had a hard time with a flatmate like you."

"You didn't even know who Copernicus was until last week" John pointed out, smiling despite himself.

Sherlock snorted disapprovingly and tightened the hairs on the bow.

"I don't care about his astronomical work" he said, casually motioning heavenwards with the bow before coating it with the golden piece of rosin. "But for a sixteenth century mathematician he had some interesting theories."

"Really" John said simply, half expecting an introduction to the interesting theories in question, but Sherlock said nothing of the sort. Instead he placed the violin on his shoulder and gave John an inquiring look.

"What?"

"Any particular requests? Not Chopin, anything else is fine."

John blinked. In the short time he had lived here, he had never been asked such a question. He had thought that Sherlock played only for himself, and that whether he was composing something of his own or playing someone else's music, Sherlock did not care if anyone was listening or what they might think of it. Maybe he had been wrong about that.

"I'm… not very familiar with violin music" John said uncertainly, which was absolutely true.

"Bach it is then."

And he began to play. The melody was soft and slow and quite unlike anything John had ever heard Sherlock play before – the word meditative came to mind, as opposed to engaging or rapid or even furious, which were much more common themes – and it was faintly familiar, even to John.

It was also soothing.

Watching Sherlock play was almost as amazing as it was to watch him at work. Hard as it was to combine the energetic, workaholic detective with the calm violinist, they fit perfectly together all the same, dedicated to what they were doing and excellent in their execution. However enticing it was to watch though, John found it increasingly difficult to keep his eyes open.

Inhale, exhale.

The images that had played themselves out on the insides of his eyelids were fading. The horror of war was apparently no match for Johann Sebastian Bach. Who would have known?

Inhale, exhale.

Sherlock was still playing, a new variation to the melody now but still calm and soft. The tea was all but forgotten on the table and John felt a familiar warm drowsiness settle just as he remembered from where he recognised the melody. It was a lullaby, one Harry had loved as a child. Bach. Huh.

Inhale, exhale.

It was like floating, listening to the violin. No, this was certainly not something Sherlock would play for his own sake. This was…. this was…

And with that oddly comforting, half-finished thought, John Watson fell asleep.