So in AotD, the Doctor gave Amy his nano-field bracelet. What if he became infected, but it’s been progressing super slowly, because he’s a Time Lord?
'Subtract love, add anger’ - a recipe for a Dalek, yeah? And the Doctor has not been himself in some of the episodes. Almost shot a man, cold-bloodily killed that guy in DoaS, called Amy’s and Rory’s lives ‘small’…That’s not like the Doctor we know. Sure, he can be really dark and scary sometimes, but he’s the man that never would, remember? He gives options and second chances, he doesn’t just kill. No life is small - his words.
I’ve been regarding all of that as him being bitter about losing the Ponds (I assume the events of series 7a didn’t happen in the shown order), but now I’m starting to wonder.
It would truly be the ultimate irony - and the 50th anniversary worthy plot - that the Doctor is turning into one creature he hates more than anything (well maybe not more than himself).
Oswin deleted the Daleks’ memory of the Doctor, so, as the infection progresses, the Doctor is forgetting who he is. he will perhaps lose all of the memory of his own and “Doctor who?” will actually be asked by the Doctor himself at the point when he can no longer remember who he is.
Another idea: What if, after losing the Ponds, plus slowly turning into a Dalek, his reality is so horrible he can’t stand it, so he invents another one - just like Oswin did? What if Clara isn’t real, but is a message that keeps being sent to the Doctor, trying to reach through to him? The TARDIS phone should not be ringing, it’s not connected to anything, it’s fake - it rang because that world is not real and someone is trying to reach through those walls the Doctor has built in his mind.
There are just so many possibilities at this point, I don’t even know what to think anymore.