Dean raises his brows. Somehow he doesn't believe it. Sure, she's not in distress, but she's definitely flirting with disaster. There's something else going on here.

"So walks in the middle of a monster infested darkness is just a hobby for you, then? Hey, If that's the case sorry t'interrupt."

It's clear sarcasm, he's prying for answers subtly so he doesn't make her feel threatened by coming on too strong.