Sometimes it's very easy to say "Oh I'd do the moral decision", but humans have a biological urge for self-preservation, this urge can very easily get in the ways of morals or logic. When you're in the state of mind of fear, cold water surrounding you, all you can think about is the pain of drowning, losing your life, all your progress that you have ever made ended and for naught. I think most people then wouldn't be thinking "I'll go down with the ship" or "I'll sacrifice myself to save another person". Fear is one of humanities strongest and most motivating factors, usually stronger than morals and ethics.