Sort of a relief that it imploded.
The idea that they were stuck with limited air banging away on the carbon fibre hull when there were no realistic plans to save them, even if they were located, was a bit horrifying.
From what they said on the radio it imploded about 3/4 way on the descent, without any external trigger there wouldn't appear to have been an awfully large safety margin.
With some 5000psi pressure, might even be difficult to design the safety margin into that submersible, don't know if it's even possible to be honest.
Certainly I wouldn't hang myself on a bolt if there wasn't a safety margin of at least 3.