Move. The word he repeated in his head over and over, the first word his subconscious brought to mind when he awoke from the darkness of his dreams. He had to move, had to move on, had to keep moving, pushing each foot in front of the other. He had to move the pain from the forefront of his mind, into the back, forcing it to become a dull ache. But it didn't ache, it burned, the pain shot through every thought, every action. Keep moving, his daily motto. Sometimes, most times, though this mantra of his, led his feet straight to his friends' grave. Sometimes he talked, talked to the headstone like it could hear, like it was Sherlock himself. Other days he stood quietly, silently cursing the man in his head. He eventually had to turn away, and walk, move.
When he received the looks of pity from both Lestrade and Mrs. Hudson, for a moment he was frozen, stuck in pure pain. And for those seconds, he forgets how to breathe, how to function, how to remember a time before Sherlock had bullied his way into his life. Move, and he quickly distances himself from them, from their constant reminder of his loss.
Move, the word he suddenly, literally, takes to heart. He moves to a different flat, away from Mrs. Hudson, away from reminders. He had never intended to twist the meaning of that simple word into running away; in the beginning it had been his only motivation that he had to keep moving on with his life. But instead it became his excuse, allowing him to leave everything behind in order to avoid pain, like a coward.
When he stands with Mrs. Hudson at his grave, and they talk, he can't force himself to run, to move. And later when she leaves him alone, he begs Sherlock, begs his best friend to have performed a great miracle. But suddenly he pauses, if this were so, if Sherlock really had deceived the world like that, if he ever came back he would slap Watson, verbally that is, or possibly physically. He cringes at the thought; he would be reprimanded for moving, for moving away from everything, for avoiding the things, and people that had once made up his entire life.
He walks away from the cemetery, one foot in front of the other, but suddenly pauses, goose bumps on his neck at the feeling of someone watching him. But he doesn't have the luxury of being able to stop, of pausing, and so he pushes forward; keeps moving but not running away anymore, only moving forward.