To paraphrase General George Pickett*, I think 6 kilo-psi might have has something to do with it.
*When asked, as he often was, about the failure of his eponymous charge, he would reply, “I think the Yankees might have had something to do with it.”
Especially since the hull of that craft was designed by politically correct technicians, and made with paper mache and duct tape.
Designed to implode, I'm surprised that it made it down to see the Titanic before it was crushed {if it did}.