In the second mission (Arctic level) first phase where you start with the hovertank, 
turn right slightly until you see a pad/chopper. Go to it. When you get in front of 
it, turn right slightly until you see a light bulb-shaped radar. Destroy it. Go to 
where it used to be, then turn right slightly to see two port-a-potties. 
Shoot them to see a man on the toilet, reading a newspaper.