From where you begin, turn left and pick up the guns on the table. Now turn around and wait for the door to open. Take out the guard and go through the door, then turn left and take out another guard. Proceed down the hall, turn left, and take out another guard. Go to the door where the guard came out of and prepare for another guard. After the guard is down, run to the desk to pick up an 870 combat shotgun with seven rounds. You may lose some health and ammunition, but the reward is a powerful weapon.