Of course, at or near the maximum depth exposure would have meant certain death, however, a report I read stated that contact with the submersible was lost less than 2 hours after the dive. If there were unfavorable or warning instrument readings within the submersible at or around that time, perhaps they could have ejected if it had been possible to open the hatch from within.
I'm also curious to know if it can ever be determined if there was an engine failure.