No, they did not know they were signing a death sentence. They expected to get extracted, as their commanders and the helicopter guys are just as good at their jobs as the SEALs are at theirs.
the helicopter guys went in there without security, the apaches, as time was critical. The apaches were sent on another mission, poor planning and logistics. The helicopter guys died trying to rescue the SEALs, just as dead as the SEALs, just as willing to face death as anyone else in the military.
But rules and moral code do not get put aside just to stay alive. Acceptance of death is part of it.
Murphy goes to make the radio call giving Marcus his ammunition. Marcus is arguing because he wants to be the one to go, but he knows Murphy has to be the one to go.
In hindsight the situation looks different. They didn’t expect the mountain on the other side, poor planning? But the non combatants do not get murdered for that mistake.
Good on ya. Agree with all.