@BCTheEntityThe wetsuits are fine, as are most things they wore before they ended up in the Underlake. The various other pieces of equipment are trashed.
@Draconequis Thanks for the good review of the proposed Soul Modes. To cover your argument for "caves are cold", I think it's actually the case that the average temperature of any given underground location on the planet increases the further down you go, so if anything, this cave system would end up being relatively warm without something being in place to deliberately keep it cool. Just a thought.
@Kafka Komedy To be fair, the players did have to swim down far enough that they stopped seeing light underwater. That suggests a pretty significant distance downward. I have a link here about it, etcetera.