I am a wealth of second hand military stories if nothing else, and as the OP I feel justified in sharing a story in a similar vein but for a different service - to whit, the United States Navy.
One of my American relatives was the reactor officer on a boomer back in the 1980s, I forget which one but I do recall him telling me she was later placed into service as a tethered training vessel for trainee nukes, and he was refused access to her during a subsequent stint as a civilian contractor even though he was her reactor officer for many years and also taught at the US Navy's nuke school (his Admiral Rickover story is the stuff of legend and worthy of a thread in its own right, but I digress, so on with the "moment" story.)
He had only recently qualified as an OOD watchkeeper, and as the youngest and most junior officer so qualified he pulled the worst duty shift - the early morning hours, but for that time he had full command of the ship. They were crawling along at 4 knots or so when the sonar room whistled him up with a passive contact dead ahead, a minute later when he asked if there was any change in target bearing the sonar operator replied that there was not - it wasn't crossing, it was coming straight at them. He couldn't give their position away with active sonar to warn what was now known to be another sub, if he dived or planed up he could just as easily hit them as if he stayed on depth. So he changed nothing and summoned the captain from his cabin. Just as the captain rushed into the con wearing nothing but his underwear the entire submarine lurched violently to one side, they never knew how close what was later identified as a Soviet hunter killer came to them, but it was very close - he told me he had nightmares for a long time after that, knowing how close he came to what would have been the worst submarine disaster in history. Apparently Soviet submariners who reached the end of their patrol routinely headed for port, wives, girlfriends, and vodka (in that order) at flank speed as stealth was no longer a concern at that point and they just wanted to get home.
I'm sure that this and a thousand more cold war stories just like it will never be made public, but there it is. Today he works in nuclear safety having reached the top of his game, but he very nearly didn't....