As for "unexpected," I'd worried about infection from all those bites, but hadn't thought of the possibility of fast-acting venom. The bears are playing the expected role of being the first casualties.

Higgs can take a lot. The Fandom wiki gives his name as "The Unstoppable Higgs," a rare case of their treating an epithet as a canonical name. He'll probably survive, but he may be out of action for a long time.