Howling:What was in the Doctor's room in God Complex?

I was watching this episode again today and started thinking about what was in his room, so I've been looking for some theories on what was in his room but nobody's said mine so I thought I'd throw it out there. I think he saw David Tennant (himself as 10) having sex with Rose. Here's why. Every room isn't necessarily the person's greatest fear; they always refer to the things in the rooms as "bad dreams." I mostly think this because as he leaves, he puts the "Do Not Disturb" sign on the door, which sort of signals something is going on inside he wouldn't want anybody else to see. This seems like it would logically be his worst dream because of how in love with Rose he is, but didn't get to be with her even though she got to be with him. Has anybody else thought of this?