Like being trapped inside a big metal tube with a bunch o' dudes?
Listening to the hull creak as it gets compressed a measureable amount.
Listening to depth charges getting closer, and wondering what it takes to overpressure the hull.
Looking at a controller for 4 pumps, 2 are danger tagged out of service, 1 is being used for low power operations, and the last is yellow tagged "To be used in case of high power ops during incoming torpedo attack only". And realizing that you have crossed a "line" in the ocean and that navy has decided to try to find you so they can put pictures of your broken hull on TV.
Watching the depth gauge first go past Test Depth, then rapidly approach Crush Depth.
Watching the man in front of you take the ladder too fast, causing him to drop down the hole right in front of you. Hearing the femur actually snap, then his bloodcurdling scream because his foot slipped off the rung. As he accelerated down, his foot went between rungs getting caught between the rung and the splash shield as his body continued down causing the leg to bend 170 degrees.
Then the screams as they have to hook under his arms and hoist the body back up causing the body to undo the 170 degree angle.
Joking with a shipmate as we "broke down" cardboard boxes, to take off ship so we'd have less garbage to dispose of at sea. Watching his face as his razor blade sliced through his femoral artery, red blood shooting out like a Monty Python movie. Using my Boy Scout First Aid knowledge to slap the cut and seal it, fortunately the razor sharp cut sealed right up. Pull he hand off, squirt. PUt the hand back it stops. First Aid is good. Next stop, YELL for someone to go get the DOC (actually a corpsman). Listening to the reply that doc is on vacation. He is the ONLY medical personnel the sub carries. I am "the man" until we can pressure bandage it and get him up to medical on the submarine tender down the pier.
During a storm, at night, on the surface as a phone talker asking the lookout what those lights were coming at us. His response, those are our running lights reflecting off an oncoming wave. Telling him, that can't be, they're getting higher up. Then seeing the darkness coming forward as the wave blots out the stars as it sweeps over our tiny raft as I say "OH ****ING ****!!" over the sound powered phone system.
Being on an actual Repel Boarders action (not a drill) because the topside watch on the sub next to us went crazy, pulled his .45, pointed it at the OOW (Officer of the Watch) and said "I want a chair, now". While standing there with .45, and with a few people either with .45 or .308 (maybe 30-06), looking past the submarine to the submarine tender because the rapid response team showed up, were lining the rail, with their rifles pointed at the crazy guy. Called my chief (in charge of Repel Boarders, and a TEXAN) pointed to the rifles and said, hey chief, those gomers miss any shots, where are their bullets going. Hint, they would be heading at our submarine, and the idiots in the Repel Boarders Team.
FIRE IN OPS COMPARTMENT LOWER LEVEL! FIRE IN THE LAUNDRY! RIG FOR GENERAL EMERGENCY! BRINGING SUB TO PERISCOPE DEPTH.
Just a note, fires don't just burn there. The heat travels down the metal and starts fires away, like in a trailer flre.
Also, fires suck the oxygen level down. Hint, oxygen levels are VERY important to submariners.
JAM DIVE! LOSS OF DEPTH CONTROL! LOSS OF HYDRAULICS!
This is bad because well, we can only go so deep. Loss of depth control sounds simple and easy. It's not. And hydraulics are heavily redundant. You CAN'T lose them. Till you do.
Watching the SEALS come down the ladder short one man.
Those are maybe a small percent of the things that I dealt with.
So, being trapped inside a big metal tube with a bunch o' dudes it is.
A large cigar shaped tube full of seamen.