When Nadine is about to get drowned with full of water in her room and her friends able to open room's door, water entered second room with only under the door, which was impossible. All water should like explode to other room, also with open side of submarine, water should still get in submarine after opening the door.
When Stan went out the torpedo tube at the bottom of the Atlantic Ocean virtually none of what follows is remotely realistic. Assuming that Stan didn't experience lethal blunt force trauma from any part of the process, first, he would have been met with the pressure of thousands of feet of depth in a short time span causing Barotrauma in a fraction of a second and in the time it took to flood the torpedo tube, among other things, would have caused his eardrums to rupture rendering him totally deaf, yet when he is back aboard the U-boat he is able to hear and communicate with his crew mates just fine.
Next, Stan would not have accomplished his goal of reaching the other side of the boat for two reasons. 1. He was at least 3 times deeper than the maximum depth that light can penetrate the ocean and would have been unable to see where he was going, which means Stan would have been effectively blind and deaf and unable to tell up from down or even where the U-boat was while he was swimming alongside it, and 2. he would have experienced the effects of Nitrogen Narcosis very rapidly which would have resulted in hallucinations, euphoria, and dizziness were it not for the fact that the Nitrogen found everywhere in his body would have instantly turned into an anesthesia and if nothing else would have put him unconscious almost instantly, killing him moments after the torpedo tube flooded.
Assuming an alternate reality where somehow none of these things managed to killed him in the first few seconds in water, Stan would have been far more likely to have drowned from laughter due to extreme intoxication and hallucinations than to have made it back to literally any part of the U-boat.
Next, Stan would not have accomplished his goal of reaching the other side of the boat for two reasons. 1. He was at least 3 times deeper than the maximum depth that light can penetrate the ocean and would have been unable to see where he was going, which means Stan would have been effectively blind and deaf and unable to tell up from down or even where the U-boat was while he was swimming alongside it, and 2. he would have experienced the effects of Nitrogen Narcosis very rapidly which would have resulted in hallucinations, euphoria, and dizziness were it not for the fact that the Nitrogen found everywhere in his body would have instantly turned into an anesthesia and if nothing else would have put him unconscious almost instantly, killing him moments after the torpedo tube flooded.
Assuming an alternate reality where somehow none of these things managed to killed him in the first few seconds in water, Stan would have been far more likely to have drowned from laughter due to extreme intoxication and hallucinations than to have made it back to literally any part of the U-boat.
Captains can not perform marriage ceremonies. Another regular error in films.
The U-235 was not commandeered by resistance fighters and delivered to the Allies. It was sunk in the last days of the war when a German torpedo boat T-17 mistook it for a British submarine and depth charged it. All 46 men perished in the attack.
Stan performs CPR on Nadine. While CPR can save someone who has been submerged underwater for a long time, CPR wasn't actually invented until 1960.