[That's an anxiety response. Erhard doesn't like that he's unsettled the young man, but maybe it will break him out of his shell of frosty anger. Still, he doesn't want to push too hard, too far, and leave them both out in rough and unfamiliar territory.]

Okay, Koide. I didn't mean to upset you. If you want me to leave, I will. But thank you for pointing me toward the books I wanted.