It's all AU.

Having made up his mind that by landing him here someone up there was telling him he needed a rest after what had been one hell of a year, the Doctor had decided to make the most of his enforced holiday from saving the world on a regular basis.

He ended up at the library and pottered around a bit before selecting a battered old human text on theories of time-travel and settling down in a squashy chair with his feet up on another one for a good laugh.