6x11 The God Complex

Congratulations to mr Toby Whithouse. Growing to like the man more. School Reunion was great but the Vampires of Venice I thought were a bit disappointing. Then I remembered he created the incredibly witty Being Human.
This was a good episode, compliments well Moffat's idea that the Doctor is somehow a very old and wise Peter Pan, but, as in Peter Pan, his companions need to grow up. I really hope this is not a red herring kind of thing.

I think you're slightly off the mark there.  What was in the rooms was still supposed to represent the individual's fears; the twist was just that He wasn't feeding directly on that fear, but on the faith that the victims would subsequently draw on to stave off their fear.  So what was inside the Doctor's room was supposed to be his fear.

As to exactly what was in the room, I don't know where you're getting "brakes" from; we can certainly hear the Cloister Bell, so all we know for sure that a TARDIS is within earshot, and that something bad is happening (and that bad thing is probably somehow timey-wimey.) 

I think it's probably a safe assumption that the scene through the door would be onboard, probably the console room, and probably the Doctor's TARDIS, but I will admit that at least in part those assumptions are based on my own gut feel for the style of storytelling typically used in Doctor Who   I take some of it from the... timbre(?) of the Cloister Bell - it sounds to me like the bell sounds from within the TARDIS, but not from up close - so the console room seems the most likely candidate both from that and for storytelling purposes.

So, to (finally!) get to my point.  I think it should be kept in mind that although whatever was through the Doctor's door certainly involved the TARDIS, it wasn't necessarily about the TARDIS, at least not entirely.  If it was a scene set in the console room, it could be any person or thing that could be in the console room.  "Of course. Who else." doesn't necessarily refer to the TARDIS it(/her)self.

So I think that's a thing that should be kept in mind - who was it, or was it the TARDIS?  That and the assumptions that it was even the Doctor's TARDIS we were hearing, or that the scene was onboard rather than e.g. near a parked poorly TARDIS with the door open   All of those things are the sorts of rugs that Moffat takes such pleasure in pulling out from underneath us, so I think it's worth keeping in mind.

It is mostly guesswork at this point, but for my money, it was a scene in the console room of the Doctor's dying TARDIS, and it was either the Doctor, or River at the helm.

Kal, you are spot on. Fantastic analysis.

I do agree that the Doctor's room had something to do with the TARDIS. The bell could be heard for example in season 4's "Bad Wolf" reveal when Donna relayed Rose's message to the Doctor. At that point the Doctor said it was "the end of the universe." The sound itself would suggest that it was just something really bad happening, not necessarily the TARDIS dying - I don't remember the bell ringing when River was in the TARDIS as it exploded at the end of season 5 and created the tears in reality.

But my thoughts also went directly to the TARDIS dying, that being the Doctor's biggest fear. But you raise a few valid points as to who was in the TARDIS and maybe something bad happening to them in the TARDIS would be the cause for the bell to ring. (The Doctor's "real" death might certainly qualify, but somehow I don't think the Doctor is so vain that his own death would be his biggest fear. He certainly risks his life a lot for that to be the case.)

In any case since the death of the TARDIS is a very logical conclusion I am almost certain that was not it and I hope we get to revisit that scene in the finale (or even further down the line) and marvel at Moffat's brilliance ...

"We're on the side of the demons, Chief. We're evil men in the gardens of paradise, sent by the forces of death to spread devastation and destruction wherever we go."
-- Colonel Tigh