The only what. That one takes Arthur by surprise. "She's blind? Good god. She didn't seem... hm." He assumed, at the time, that she could see his hand in order to shake it, but... huh. "I must have been mistaken. God, I'll have to start actually returning books in braille to the library."

A dry joke, but a joke nonetheless, as his irritation passes with the evolution of the subject.

At Crichton's prelude-to-confession... he pauses, and frowns, though it's a frown of attention -- and, faintly, of concern -- rather than one of anger.

"Go on."