Rose has dealt with a fair share of humans shouting at her for inadvertent damage caused during their fights with corrupted beasts, so she doesn't seem all that phased by Wash pretty much screaming in her face. She waits for him to finish, and then responds calmly. "I know. That's why I made sure he got back here safely. His injuries were my fault, and if my tears still worked, I would've taken care of them myself, but they don't. That's why I'm telling you, so that you can know to give me some space in our next fight." Obviously, it was an unpleasant fact from how everyone reacted, but she still felt it was important for them to know, so it doesn't happen again.

He's not telling her anything she doesn't already know, really. She just doesn't get why he's quite so mad about it, when Casey still wasn't hurt that badly- he likely would've been hurt worse without her help, after all. Still though, she does disagree about leaving him behind because of a lack of control. From what she's heard, pretty much none of them have very good control of their powers yet, but that doesn't mean they can just let things go until they've got it figured out. Rose at least has the sense to recognize now probably isn't the time to start arguing about it, though, and doesn't say anything else.