I'm really straining to find anything wrong with that episode...
thing that I find wrong with it, which is the same thing I find wrong with this whole half of the season, is that the Doctor is not trying at all to solve the mystery that is Clara.
Even when Vastra and Jenny asked him about it, he basically shrugged it off. I was really looking forward to their return because I thought that finally the Doctor might have to do something (or at least say something
) about The Impossible Girl, but he didn't.