In series 6 of the new Doctor Who series, The God Complex episode, there is a room for everyone (maybe even Rory, we don't know for sure). Amy saw herself waiting for The Doctor as a child. It scared her and reminded her of her faith in The Doctor and made her reach for her faith, which the Minotaur would feed on.
There was a door for The Doctor (Room No. 11...dun dun dun duuun), which he opened and looked into. He said:
Who else?
Who was he referring to?
Since in The Time of The Doctor, we saw that it was the crack in the wall. But who did he see?
I understand that this may just be something he said off-hand. But I am curious.