U.S. Marine Corps Cpl. Nicholas Muller, left, an administrative specialist and Gunnery Sgt. Christian Caballero, right, a ground operations chief, both with 4th Civil Affairs Group, Force Headquarters Group, aim their weapon at a simulated active shooter at Naval Operational Support Center & Marine Corps Reserve Center Miami, June 7, 2019. All 160 Marine Corps Reserve Training Centers are expected to exercise their active shooter emergency action plan semi-annually with their Inspector-Instructor staff and Reserve Marines. (U.S. Marine Corps photo by Lance Cpl. Jose Gonzalez)