Start a new game, and when you enter the main room, go to the bathrooms. Look for a guard who is getting ready for work. Note where he is then quickly get your armor and helmet on and run to the nearest sink. The guard will start to approach your sink. When he is starting to get close, turn on the sink by pressing [Use] and move away so he can use it. While he washes, get directly behind him and start pressing [Use] about once every half second. He should be saying "Calhoun, I'm...", "Shouldn't you be on?", "Swing by later and...", etc. so he gets cut off every time. Soon, he will say"Ouch, Ooof, Arrgh, Ouch". Back away, the screen will turn black, and will say that you hurt or killed someone with a firearm, and will start over. What makes this interesting is that you have no gun when this happens.