Capt. Anastasia Corker of the 433rd Aeromedical Staging Squadron demonstrates how to drink from a canteen through her gas mask during the Steel Thunder exercise Nov. 5, 2016 at Joint Base San Antonio-Lackland. The exercise is designed to test the unit’s responsiveness to a Chemical, Biological, Radiological, Nuclear and high-yield Explosives attack and its effectiveness while wearing the Mission Oriented Protective Posture gear. (U.S. Air Force photo/Senior Airman Bryan Swink)