Staff Sgt. James Grueser, 9th Security Forces Squadron, leads a team of defenders during an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Security Forces utilize the M-4 Carbine to combat close to medium range threats. (U.S. Air Force photo by John Schwab/Released)

9th Security Forces members respond to an active shooter exercise at the 548th Intelligence, Surveillance, and Reconnaissance Group building on Beale Air Force Base, Calif., Feb. 5, 2014. Security Forces utilize breach equipment to gain access to barricaded and locked doors. (U.S. Air Force photo by John Schwab/Released)

Members of the 548th Intelligence, Surveillance, and Reconnaissance Group, evacuate their building during an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Simulated victims were added to the scenario to create a sense of realism. (U.S. Air Force photo by John Schwab/Released)

Beale first responders aid a simulated victim during an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Simulated victims were added to the scenario to create a sense of realism. (U.S. Air Force photo by John Schwab/Released)

A Yuba County SWAT team participates in an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. More than 20 base and local agencies participated in the exercise. (U.S. Air Force photo by John Schwab/Released)

Master Sgt. Gina Ennis, 9th Civil Engineering Squadron, assistant chief of operations, participates as the incident commander during an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Local and county law enforcement also participated in the exercise. (U.S. Air Force photo by John Schwab/Released)

9th Security Forces members respond to an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Security Forces members utilized blank rounds to create a sense of realism. (U.S. Air Force photo by Tech. Sgt. Ricky Bloom/Released)

A 9th Security Forces member clears a room during an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Security Forces members utilized blank rounds to create a sense of realism. (U.S. Air Force photo by Tech. Sgt. Ricky Bloom/Released)

9th Security Forces members secure a building during an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Simulated victims were added to the scenario to create a sense of realism. (U.S. Air Force photo by Tech. Sgt. Ricky Bloom/Released)

Members of 9th Security Forces and 9th Medical Squadron transport a simulated victim during an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Simulated victims were added to the scenario to a sense of realism. (U.S. Air Force photo by Tech. Sgt. Ricky Bloom/Released)

A Yuba County SWAT team participates in an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. More than 20 base and local agencies participated in the exercise. (U.S. Air Force photo by John Schwab/Released)

Beale medical staff tend to simulated victims during an active shooter exercise at Beale Air Force Base, Calif., Feb. 5, 2014. Simulated victims were added to the scenario to create more of a sense of realism. (U.S. Air Force photo by John Schwab/Released)