MINOT AIR FORCE BASE, N.D. -- Airman 1st Class Shawn Parkins, 5th Security Forces Squadron, simulates opening fire with his M4 rifle on a convoy during a force-on-force exercise here. A1C Parkins posed as an enemy combatant trying to attack a convoy. The exercise helps train security forces members how to react while taking fire from enemy forces. (U.S. Air Force photo by SrA Christopher Boitz)