"It failed after 25 dives" is not a 4% failure rate if the failure was caused by deterioration over time (as it likely was here). It's a 100% failure rate over the full life of any given Titan sub. They'll all implode, given enough trips.

Moreover, both 1% and 4% are horrible failure rates for anything meant to carry passengers. Example: the risk of dying in a commercial plane crash is 1 in 11 million [1]. The risk of dying while skydiving is less than 1 in 300,000 per jump.

This guy was taking extremely unreasonable risks.

[1] https://www.pbs.org/wgbh/nova/planecrash/risky.html

[2] https://dzoneskydiving.com/articles/how-many-people-die-skyd...