Wow. You did a marvelous job with that - even though I'd read the warning and even after he'd thought "too quiet," I was completely taken by surprise, you'd lulled me into feeling like everything was going along quite normally.

But wizards are incredibly resiliant, as you already established with John falling off the broom. And their health care system is amazing - if there's any life left in a person they seem to manage to put them back together again. So I'm going to choose to bet, at this point, that most of the people in that explosion might come out horribly injured and having to spend months submerged in gels regrowing their limbs and faces, but you probably haven't killed Arthur Weasley. I hope.