When I leave base on a patrol, I have every intention of returning the boat and crew.
If I'm detected by an escort before getting into attack position on a convoy, my immediate goal changes from attack to evade, even if it means letting the convoy slip by so my boat isn't destroyed.
Everyone plays the program (game or sim, you decide) different, just like how much salt someone prefers on their potatoes or how well done they want their steak.
I made the mistake of being in a hurry to get into a harbor to photograph some ships, slipped inside the destroyer patrol, running deep and silent and went to x32 time compression
swish, swish, swish.... BOOM BOOM
My mistake for rushing the game at TC. On the PC we can just load the last saved game and learn from the mistake to not do it again. The only depressing thing is realizing you didn't save