The Doctors Three
I suppose most of the time they do. But there are still the times when they don't. And far too many who prefer attacking and destroying and asking questions never. Such as the bit with the Silurians. Oh wait, that was the Eleventh Doctor who had that particular mess. Sorry. Some of these memories get jumbled.
No, she didn't, but at the same time it wasn't particularly her decision to help with. She isn't a Time Lord. Just as we are not human. Earth is not our home, though we have come to love it in spite of the human race trying to do its bit to do itself in.