His first thought when she asks if he is afraid of mice is to feel offended and embarrassed. Afraid of this tiny little thing? How pathetic does she think he is? But a moment later, he thinks... there's something a tiny bit nice about her making that mistake. It is dependent on her not realizing that he is a horrifying monster, and thinking he is just... normal.

But how to correct her that he's not afraid, he's just uncomfortable with rodents because when he was a kid his father had used them to train him to harness his powers and to desensitize him to killing? So, he lets her be wrong, says tightly:

"Something like that."

Ben can tell she's having a hard time back there, so he just does his best to stay as still as he can, even if it's awkward, bending down like this and with her standing behind him rooting around in his hood with her hand. Then it's over, and he lets out a sigh of relief watching the little mouse make a beeline for her braid.

He can smile, then, because Cho seems completely comfortable having the little thing running on her, and if it's on her it's not on Ben. She doesn't move for the crate, so he assumes this isn't a good specimen for some reason. Too small for blood tests, maybe. Can't have more than a thimbleful in there.

"He's sure not scared of people, is he?"

And, as is his way, now that he's had a moment or two to think it over, Ben loops back to what she'd said earlier, and comments:

"Don't take this the wrong way, but your family sounds intense."