If you decide to cook that guy stuck in a chamber, instead of saving him, a horde of monsters attack you. Saving him yields no monsters.
Also, in that room he has a full ammo arsenal. Just quick save when you get there, chamber frag him and then reload the game for the achievement. Let him open the room, you get your stuff, kill him and THEN take his PDA and have the best of both worlds. >:]
Haters mean you're doing your job right. GT and PSN: sinyx