Not to poke holes in everything you just said.. but I'm going to do just that.. 1. Naval mines are magnetic, you bring a metal vessel anywhere near them and you're gonna have a bad time. (Hence why minesweepers are generally wood hulls) 2. How is deciding when you're discovered in any way a knock on realism? In real life you almost never get discovered when it's convenient for you. 3. Few things here, the mission is a bust if A. the enemy kills you, or B. the enemy radios to their bros and lets everyone know that you are there.. A. will happen if you run, because you're not really a hard target as you try to swim away. B. will happen if you don't kill the patrol.