How fast did the people in it die?
Of course once the sub filled with water they would die instantly because it would reach insane pressures (300-400 ATM or 5800 PSI)
4 points
And because what failed was the carbon fibre composite pressure vessel, it probably didn’t even give any warnings to make them worried. It would be like squeezing a glass bottle, everything will be perfectly fine until it just instantly shatters.
3 points