Sherlock lay in his bed and stared at the ceiling. He had only gone to bed because John had told him to and he didn't want to see the empty blank agreement that would appear if Sherlock protested. He looked up at the ceiling and noted the bit of plaster that had flaked off since he had been here last. He took note of the blond hairs that were on the pillow beneath him as John had slept in his bed. John would never say so of course but it was true. He closed his eyes and breathed in and out. He remembered the moment when he had felt an emotion he hadn't thought was possible. He had always considered himself incapable of emotion and certainly it had seemed true but t some point it had changed.
Sherlock breathed in and out slowly, regulated. The walls were thin and he could hear John moving about through the walls. He heard him in the living room and considered getting up, to go to him, but he found he couldn't. He listened to John turning in his sheets. He heard the breathing become more regular and slow and decided he was asleep. Sherlock listened to the voice that he had heard call out so many nights before.
Sherlock counted the heartbeats as he listened to the other man. It was as a bar of music like his violin. Two beats in a bar. After a while he heard John's voice, "Sherlock? Sherlock, please, come down." So on so forth and eventually, "Please, he's my friend let me through." This was how the nightmares always started, Sherlock decided, remembering the time when it was not his name John called out but distant comrades that Sherlock had never bothered himself enough to ask about.
Sherlock wished he could go and comfort John, hold him, like he might have had the courage to do three years ago but lacked the initiative. Sherlock turned and watched the wall instead, the three spiders on it, fastidiously ignoring each other. He closed his eyes and blocked out everything, one by one. Sight, gone. Breathe in, breathe out. Hearing, neutralised, but still his brain was too busy, still Sherlock counted his heartbeats. One bar, two bars. He knew it wouldn't work, but he continued to count out his silent music until the dawn and even then he lay still until he heard John begin to move around.