I acutally got my PC's to start the adventure with the battle since the frigate that was taking them to their mission was badly damaged, and there had decompression issues to face as they made it to there Drop Pod. They even left their helmets on until a Cultist Champion challenged them to single combat. And like any great space marine hero he took off his helmet to face the vile wretch.
What happened next, you guessed it. Power sword to the face. Now it says something about what it means to be a space marine when a power sword to the fce doesn't kill you out right, in fact it didn't even take my player down into the crit ranges. He killed the Cultist, but he failed to make it look really cool and inspire his troops.
We shall see. Will he where his helmet in the next adventure? I know my GM-PC won't I think he'd rather die than mess up his awsome Spacve Wolf face-braids.
This isn't really a question, just an observation. Space Marine Heroes almost never where their helmets. I can just imagine a sargent training new recruits. He shows each of theme the helmet and then berates them all in advance for not wearing it.