Sherlock doesn't let John fall even when he loses his balance the next two times. The smaller man's weight is unwieldy because of the odd ways his disoriented body tries to correct his inebriated stumbling, but for the most part, they work together until they're at the top of the stairs where Sherlock begrudgingly unhands John so he can make his own way into the upstairs bathroom or to his bed.

He plans to stand there at the doorway until John's settled and he doesn't expect his presence to be appreciated. It doesn't matter, since he's only doing what he wants to do in this. That's how it's always been and how it always will be.

He's just folded his arms and started leaning on the door frame when John turns to face him. Then he asks that.

'Why did you even come back?'

The question feels like a punch to his gut. Sudden, painful, and leaving him in a momentary state of not being able to answer in any meaningful way. He'd thought that hearing the question 'Why did you leave?' would have been the hardest thing but he'd been wrong on rare occasion before.

Because I wanted to. You. Mrs. Hudson, Lestrade, Molly.

"The same reason I left in the first place," Sherlock tells him coolly. He hadn't ever addressed the answer to the other question in words, so this might be a way of cheating and getting out of putting things into words that he felt were better expressed in actions and unspoken assumptions.