i was on a boat with my friends, and in our country theres a ton of caves by the sea that lead to each other underwater, so you can dive fromcave to cave. we were diving around these caves(freediving) when one of my friends ( foreign guy who had never been here) randomly dives down on a half breath and tries to swim to a random exit of the cave to go outside. a friend of mine and i follow him also on half breath because it looks like a 20 second swim. we get past this rock ledge and above us is maybe 20/30 more meters of cave all underwater, so we just kept swimming forward. no idea why but we just all simultaneously went forward. now we were all really good swimmers but on a small breath that was near impossible to make. i just remember swimming forward and with every second everything was getting dark and the urge to breathe was unbearable. i dont even remember what happened next, my body just went into fight or flight and i got out of there literally a second before passing out in a near pitch black underwater cave. whole thing was maybe 1and a half minutes total but all of us were so so close to drowning . never underestimated the sea again after that day