“active shooter” drill

First Responders Hold Active-Shooter Drill At NJ SchoolThe drill at Wayne Hills High School was designed to test officers in a double threat situation: two attackers, one with a gun and the other with a bomb.
Law Enforcement Agencies Hold Drill At One World Trade CenterThe "active shooter drill" used mock gunmen firing paint bullets.
Law Enforcement Agencies, Volunteers Take Part In NJ ‘Active Shooter’ Drill The drill at Liberty Middle School is designed to test the response of a dozen law enforcement agencies to a situation similar to last year's mass shooting at Sandy Hook Elementary School in Newtown, Conn.