"I don't have it in me to kill unless I absolutely had to." Caitlyn said which meant she wouldn't cause she wasn't that kind of person. She thought that a psychopath traveling with them might not be the best idea but if she was in his shoes what would she do? She would fight tooth and nail wanting her friend back. "Do you know what changed him from who he had been to who he is now?" She asks curiously. Maybe they could change it by going to the source of the problem to begin with.
Rose reached out placing her hand in the Doctor's knowing that he would do anything to make sure the other Time Lord lived. "I won't kill 'im." She promised. Course she had no idea that the other presence in her would do [I]ANYTHING[/I] to make sure her Doctor was safe.