I remember an awkward TED interview with Victor Vescovo when he was talking about being in a submersible miles down and what could go wrong in such situation's. He made a good point: those kind of situation's, when something goes wrong, you wouldn't even know it.
The majority of any given point in the world’s oceans are deeper than the crush depth of any submarine. Submersibles, not so much (modulo Oceangate’s).
I don't know what's worse: a gradual realisation that there's going to be nothing that anyone can do to prevent your sudden, violent death or a gradual realisation that you're going to be slowly asphyxiated.
https://www.ted.com/talks/victor_vescovo_what_s_at_the_botto...