I would be a surviving space marine. Not the guy who bites the bullet to set the tone of the scene, but the guy who, after witnessing his brother-in-arms die for a cheap scare, gets up from cover and opens fire.
I might even lead a squad of escort mission soldiers. The ones the Chuck Norris-type main character would have to protect. Of course, we couldn't die and cause a game over, but we'd keep the mission rolling on. I'd be blabbering about pointless military jargon into the hero's headset for the whole time, though.