If you mean the OceanGate submarine, it seemingly spectacularly imploded after its carbon fiber structure gave in to various microfractures. If that really is what happened, the water pressure killed the crew faster than their brains would've processed anything.

[–] BudgetBandit@sh.itjust.works 1 points 1 year ago

The pressure does not kill. Whales live down there. It’s the compressibility of water. At this depth it’s about 4% compressed. The cabin has 1 atmosphere of pressure, the water around it about 100. Through a microfracture water shoots in at the speed of sound in water (3x speed of sound in air) - that’s about 100 bars. That’s like a water jet cutter. It rips the microfracture open. Within a tenth of a second they get pressed to death by the compressibility of water.