Press Up(2), Down(2), Left, Right, Left, Right, B, A during game play. The message "God Mode" will appear to confirm correct code entry. Note: This only seems to effect you, and not your team or hostages.
To clear out a room, stand besides the door, as one of your teammates would have if you told him to clear out a room.
Make sure that your clip is full and the action icon does not have the brackets around it, so your teammates will not open it for you and take fire. Finally, make sure that all of your teammates are stacked up properly:
Then, rush the room with thermal/night vision (your choice) on and scan left to right for enemies. Then, strafe to the left of the door to let your teammates in. Next, walk around the perimeter of the room and when your teammates say threat neutralized (on some smaller rooms they do not say anything), your work is done.
Tracer Rounds
To get rounds that allow you to see where both the enemy, and your own team, is shooting press "up", "down", "up", "down" on the d-pad, and then click the right analog stick to "zoom" twice.
