161027-F-KC610-287
MALMSTROM AIR FORCE BASE, Mont. – Staff Sgt. Alex Callahan, a member of 741st Missile Security Forces Squadron, cordons a perimeter as a security team advances to neutralize a threat during a drill at the base clinic on Malmstrom Air Force Base, October 27, 2016. The purpose of these drills is to ensure security forces know how to handle unknown threats during an attack. (U.S. Air Force photo/Senior Airman Jaeda Tookes)