The animation looked a little weak to me, but above what I'd expect from this show, so it worked just fine. Maybe its upper-body only choreography, but it looked kind of cheap. Conceptually, though it was pretty banger. I also noticed that he parried or blocked every single strike and made clowns of them (except the girl who got a merciful neck chop).
I think it was a good idea. It isn't unreasonable to assume sour grapes would lead to false accusations, especially if only one side had visible injuries. Making them disappear (and going through the trouble) would entail him having a level of animosity that I don't think he is capable of. Not having emotions doesn't automatically make everyone disposable, does it? If they pose no threat, he can leave them be, is how I see it.