It's an odd discussion that people are saying it was about the doctor dying. It was about that as well, but moreso about the doctors soul dying. The turning point of conflict wasn't his death, but how he's going to die. As of now, his companions are dead and Davros' victory was getting him to admit he was wrong about compassion. Which still won't happen, because the Doctor is not only unkillable, he is also unmurdererable, especially if the target is a child, but that's a different discussion.