U.S. Air Force Airman 1st Class Graham Stubblefield, 422nd Security Forces Squadron installation entry controller, calls for backup to assist a simulated casualty during the 501st Combat Support Wing Readiness Exercise 20-01 at RAF Croughton, England, Feb. 12, 2020. The exercise tested the wing’s preparedness and response capabilities to an emergency situation. (U.S. Air Force photo by Airman 1st Class Jennifer Zima)