Characters and stories often take on a life of their own, and run off in some direction the author never intended. :) I've heard many writers say that, both pro and fan, and I have said it myself. But it's okay.

This was a nice resolution to a lovely story. The Doctor is indeed right, but sometimes being right and proving it can lead to undreamt of consequences that the doer of such good deeds never meant to happen. I'm glad that he didn't feel the need to prove himself right.

The ending was quite nice, too. :)