They did, it was a catastrophic failure, they were going down too fast so they tried to dump ballast when they lost contact. It was probably a woosh and then a *thunk* as it hit the ocean floor. And then they instantly died.
So, just for comparison:
Most of us live at 1 atm, which is about 15 Pounds per Square Inch. The highest inhabited community is in the Andes in Peru at 16,000 feet above sea level which is 0.54 atm. Space is obviously 0 atm.
At about 3,900 meters, its about 389 atmospheres or around 5.716 POUNDS per Square Inch
Every 30 or so feet you go in the ocean, the pressure increases by 1 atmosphere.
The pressure didn't even kill them, water drops pushed through small holes were like fucking bullets. They were shot, exploded and then crushed. You couldn't process how fucked you were before you were dead. The deep ocean is fucking worse than space. Far, far worse. You're probably also much easier to find since space is completely fucking empty. Obviously the biggest danger with space is getting there, as rockets tend to, you know, blow the fuck up.
The deep ocean may as well be another fucking planet honestly. Its hostile to life and its fundamentally amazing anything lives there.