The words are so much like his sister that he almost laughs, but he knows full well that if he does, it'll be worse for him. At least, it would be if Ro was anything like Evie. Still, he doesn't take her tone to heart, giving a one-shouldered shrug. All he can do is tell her his experiences, he doesn't know she's already well aware. If she's going to have a strop about it, that's not his fault.

"Why did you keep count?" He knows that the next question is why- but that's why did you kill them, and he imagines the reason is the same as his - because there was no choice, kill or be killed, or your friends and family will die instead. He's far more interested in how she knows that number so exactly.