From left, U.S. Air Force Staff Sgt. Shamikah Dunnings and Senior Airman Sarah Lowry, 633rd Aerospace Medicine Squadron bio-environmental engineer technicians, assemble a Radeco air sampling instrument and portable generator during an active shooter exercise at Langley Air Force Base, Va., Dec. 19, 2013. During the scenario, the technicians donned protective suits and responded to the scene of an explosion, using sophisticated equipment to detect and measure the amount of radioactive material in the air. Dunnings hails from Chicago, and Lowry is a native of Derby, Kan. (U.S. Air Force photo by Senior Airman Jason J. Brown/Released)