It's a bit more complicated than that. To change the events of someone's future is one thing, but this is... bigger than that. It's something that's unchangeable, woven through time far back before anything that she even could undo it at this point. It's... [He makes a frustrated sound and looks away. He doesn't want to say "fixed," but...] Even if I wanted to change it, for her sake, it can't be. The whole of reality could suffer as consequence. [Fixed point interference or not, Davros' reality bomb should not be forgotten.

He pauses and sighs.] She knows I'm not him, but she doesn't know the extent of it.