U.S. Air Force Staff Sgt. Robert Calhoun runs from Luck, a military working dog, after Luck received a command from his handler to attack in a controlled aggression exercise March 4, Hurlburt Field, Fla. Military working dogs are used throughout the Air Force and the U.S. military for detecting drugs and explosives, deterring threats and protecting their handlers. Both are assigned to the 1st Special Operations Security Forces Squadron.