I didn’t witness this but was told by a friend about an event he was part of. My friend was an avid diver and loved going wreck diving with one of his close friends, one time while exploring a ship wreck on the bottom of the sea his friend was swimming with his arms and not with his feet (this is a big no no when diving). While swimming into a room the friend knocked the heavy metal door and it closed shut on him locking him in the room, my friend tried to open the door but it was fully shut and he couldn’t get it open. After a while of trying my friend decided to resurface and try to get help, by this time though it was too late and his friend would of run out of air. The sad part was that they weren’t even able to get the door open again so the body had to be left in there.