Sherlock waited until he was sure that John was asleep before venturing upstairs to stand outside his room. Quietly he opened the door and stood in the doorway listening in case he had disturbed him. In the semi darkness he watched John sleep, noting the steady rise and fall of his chest and committing the sounds he made to his memory. He smiled to himself thinking about the last time he'd done this; John had caught him and had been angry about Sherlock not respecting personal boundaries.
Slowly he approached the bed, looking down; a wave of sadness passed through him as he reached out to not quite touch John, his hand hovering, wanting to push his fingers through John's hair. He was leaving, he had no option, he couldn't put John in any more danger than he already had, and he couldn't take John with him.
He paused, leaning in closer he took a chance and whispered in John's ear 'Remember me, won't you?'. He straightened and turned to leave the room, pausing in the doorway to take one last look. Closing the door silently he went downstairs and out of the building.
A car was waiting for him, he sighed as he got in, it would take him away from John, and away from England, possibly never to return.
