Here’s an idea… it seems to me that there might have been a “multiple doctor timeline return thingy” happening while they were under the restaurant. As he started exiting the room, he was emphatic that he’s been there before and, in general, seemed a bit disconnected. Understandably so. We see him go down the hall, wearing his nightdress and smelly coat, and the door closes leaving Clara to fend for herself. Exactly at the moment that Clara challenges the Doctor, if he really is her Doctor, to be behind her, 12 shows up to grab her hand with confidence and clarity… AND a nice new jacket, shirt and tie. His personality seemed different too. When Clara and the Gang return back to the mansion, the TARDIS is gone… My guess is that 12 returned from some other time to his first day to save Clara and possibly deal with Humpty in a way that only a more settled, composed Doctor could. (Those are NOT two words I would generally use to describe the Doctor!) Who knows what he got himself into when he went down that hall… Thoughts? Plausible?
