I just love how genuinely worried Subaru gets whenever Regulus landed a hit on Reinhard. Anyone else wouldn't have batted an eye because of how op he is, but not Subaru. When everyone else takes him for granted, Subaru just sees his friends possibly get hurt and wants to make sure he's fine. There's guilt too, since Reinhard got kicked protecting him once. Also, Reinhard apologizing even though it's clear if he could've gotten back faster, he would have hurts to see.