I love the way you bring it all to a head here- it flows as the best sorts of fairy tales do, and yet doesn't neglect the subtle things (and the humor) that make Doctor Who what it is.

The whole ending is wonderful, but these lines:

“I was never able to say it before, though I must have tried hundreds of times. It just kept coming out as ‘fantastic’ or ‘run’ or ‘pass the salt.’ I kept telling myself that saying it wasn’t important, because you knew, but words matter.

are absolutely perfect.