Given the setup of the episode he already knew she was going to break her wrist - that was already a given. It was going to happen no matter what he did. If he stayed it would have been HIM breaking her wrist. So basically he was fucked either way.

Argue that writing of the episode was over the top and ridiculous if you want - I'll probably agree with you. But I'm not agreeing to the idea that the Doctor was a dick given the set up of the episode.