That's the kind of question with claws. Jaws. A six-foot security perimeter. He either lies and says that it's not weird -- not at all, not one iota -- and she sees through him like plate glass, or he cops to the fact that it is very weird and then they have to talk about it. Right now, neither option sounds like a winner.

So he resorts to,

"I don't know?" with the upward, interrogative inflection that denotes he's really out of his depth.