It's just a little tricky to know where to go from here. On the one hand, going by your internal monologue he had the whole thing under control and while plenty of people were poisoned no one actually died except for Shaiapouf.
On the other hand, the only one who actually knows that is Katsuo himself, and anyone who isn't friends with him already is probably going to jump to the conclusion that he's a loose cannon who has no concern for anyone, and is using the clumsy guy act as a facade to get close and kill everybody with the NEXT summon.
They'll either be terrified, ready to murder the crap out of him, or both.