7. The Curator Is The TARDIS
Sort of an extension to the previous entry on this the theory goes that Tom Baker's curator character from the most recent episode obviously knew too much about what was going on. The basis of being that Tom Baker's curator was in fact the Moment. Which in turn was the TARDIS. See? I'm getting a headache too. So, the basis for this theory is that the Tom Baker thing was all confused and a bit of a mix up, like with the choice of Bad Wolf Rose earlier in the episode. It goes that the Moment changed appearance to encourage the Doctor but mixed up and chose an incarnation from the past and put him in the wrong timestream and so on and so forth. I can buy the possibility of number nine, but adding the Tom Baker thing to the party just muddles it all too much for me to bite. Of course this isn't the only theory on Tom Baker's reappearance...