Based on an interview I heard earlier today, I'm 97% certain these people died a few hours after their voyage embarked. The sub apparently has two communication tools available to it that would only stop working under two conditions: 1) total loss of power or 2) a hull breach/implosion. They both stopped working a little less than two hours into the trip.
The more I've learned about this sub, the dumber it sounds. Incredibly cramped/uncomfortable confines, piloted by PS3 controller, 18 deadbolts that trap the people inside from the outside, one view port that they apparently wouldn't be able to see the wreck out of anyways, materials that experts say were not up to the standard of other submersibles that travel to those depths...
Like, come on.