Well, that would be absolutely terrifying. Trapped in a subway, watching the water rise - and rise even more outside, wondering if you’ll be stuck, if you’ll drown. It’s actually amazing they were able to safely get out, given what was happening at street level.
I’m haunted by stories I’ve read about people trapped by rising water in Germany who drowned, though it occurs to me that such stories happen every time there’s major flooding in the US, something which already happens more than it should thanks to bad infrastructure and permissive zoning, and now will be routine in a post-climate-change world.