153rd Airlift Wing security forces tests active shooter and lockdown procedures
U.S. Air Force Staff Sgt. Chance Walkama, 153rd Security Forces Squadron, walks through a doorway, Dec. 18, 2015 at Cheyenne Air National Guard base in Cheyenne, Wyoming. Walkama portrayed a lone gunman during an active shooter exercise attempting to fatally wound as many people as possible before being captured or killed. The scenario was in support of memorandum sent by Secretary of the Air Force Deborah James to test lockdown and active shooter procedures in response to shootings in Chattanooga, Tenn. (U.S. Air National Guard photo by Master Sgt. Charles Delano)