Castle frowns. Like it isn't bad enough when he doesn't get subtlety. "Never mind. Point is, at least I'll have someone with a different style to practice with if I get any good. I don't know if I'll ever really be good enough at it to be worth Paul's while as a sparring partner, though."

Considering that Paul was in a wheelchair just before the last time Castle saw him, this kind of says a lot about Castle's self-confidence.