[BigWalleye]

Once upon a time, I had the great fun of riding in the Shuttle Simulator at Johnson. The cab rocked back into launch attitude, the rumblers kicked on, and we watched the “Earth view” recede through the windows, while flipping switches in response to prompts from Mission Control. Then, as we passed through 100,000 feet, alarms went off and red lights started flashing, as the Voice informed us that we had lost Number 3 Main. For seconds which seemed like hours, we punched switches, desperately trying to remember from our briefing what we were supposed to do. Suddenly, the alarms stopped, the MPDs froze, the lights stopped flashing, and the Voice said: “Sorry, guys, but you’re dead.” If we had been astronauts in training, we would have been debriefed about what we had and had not done right, but we were just guests along for the ride on an MCR crew training sim. Game over.

R/L, when the fertilizer hits the ventilation system, there is seldom feedback about how you are doing. SH3, while not a perfect sim, is like that when things go bad. Hull at 25%? Does that mean that you can take 25% more damage before your hull collapses, or that you have only a 25% chance of not collapsing every time the program checks? Got her headed back up? Well, sorry, but you are already way below the safe depth for your damaged hull and you may not make it to a safe depth. Either you make it or you don’t, and it’s up to you to figure out why. There’s not a lot of heuristic feedback. In the situation the OP described, it is possible to be "doomed" for a while before you are "dead". You just don't know and you have to keep trying. (Or hit ESC and load your last save. It IS a game, thank Heaven!)