Good, that's what Barnabas looks for in a student tbh, though he's def got a firm hand for the otherwise insurbordinate.

Barnabas will find Light bold for wishing to come along, but he doesn't disagree with it being a good way to test his skills. He is an intense mentor, and if Light wishes to challenge himself, he will not discourage him. Nothing will get him more ready for danger than danger itself. Also, what better way to humble him than for him to face the reality of combat?

Though Barnabas won't allow anything to befall him. Well, anything lethal.