TheChampionOfTime wrote: Oh also, why would breaking the fourth wall matter to a story's validity. What matters is if this story is intended to be set in the DWU, and that is undeniably yes.
I know what you're saying. I would never think of Music of the Spheres as invalid... because the Doctor meant to break the fourth wall. Similarly, in Before the Flood, the Doctor explaining the Bootstrap Paradox could simply be him talking aloud. He's always talking to himself. As long as you can explain it, there's no problem.