I think this is the most surprising thing I've seen in this game. What a sinister image to encounter in a random support event.

(In case you haven't used the card: What happens next is that Tannhauser pops out of the water, cheerfully explains that she got a nosebleed when her face bumped the bottom of the pool, and accepts Ikuno's directive to go to the infirmary even though she's basically fine.)