Huh. When he asked for his book back, she'd rather been expecting something along the lines of no, you're not wasting my time, I enjoy talking to you.
So clearly, she had been annoying. Possibly she'd tried his patience, even if he had seemed to not mind so much.
Well. All right then. "Sorry," she replied as she offered the book to him. "Didn't mean to tie up your evening for so long. Thank you for your patience," she replied, though even now she made no move to stalk off.
He was the one with an agenda and (presumably) somewhere to go to read. She was just the new girl who had to figure out this place. So she'd just ... let him go on his merry way and she'd sit here and contemplate the apparently lack of a visible universe, or something.