A member of the Crestview Police Department SWAT guards a door as their team members clear a room at the Naval School Explosive Ordnance Disposal building during an active shooter exercise on Eglin Air Force Base, Fla., Dec. 3. Police and first responders from Eglin and the surrounding communities participated in the joint exercise in which a person with two weapons entered the building and began shooting students. The SWAT team made sure the building was safe to enter. Then firefighters moved the victims out to the triage area where local emergency medical technicians provided care. (U.S. Air Force photo/Samuel King Jr.)