It makes sense, humans rarely completely keel over after a single shot to non-vitals. The "keep shooting until the danger is gone" rule exists for a reason yaknow. Honda-san being a nurse in a hospital with a vampire director is clutch for keeping the situation on the down low — "middle-schooler admitted with gunshot wound to torso" would be front page news in a country like Japan.
I also enjoy that the trick of showing characters for one frame as their old selves, while cheap, still works every time, for me at least. Very good arc, I like how this manga consistently shows such great story structure and feelings.