An Active Shooter is an individual actively engaged in killing or attempting to kill people in a confined and populated area; in most cases, active shooters use firearms(s) and there is no apparent pattern or method to how they choose their victims.
Active shooter situations evolve quickly and there is no way to anticipate their course. Typically, the immediate deployment of police is needed to stop the shooting and mitigate harm.
Active shooter situations can be over within minutes. For this reason it is important that you are prepared to act quickly to protect yourself.