Right, that's a fair point, because he doesn't need to know. It's more that he wants to know, especially as she's outright refused to tell him, and he still doesn't take kindly to outright refusal.

But eve though she's right, he's not about to admit that. Instead, he rolls his eyes, as if he's just given up on her, as if she's too hopeless for anything else. "Then if you refuse, you can at least answer questions of it. Are there other people nearby?"