The public must be prepared both mentally and physically to deal with an active shooter situation because these events are often over within 10 to 15 minutes, before law enforcement or emergency responders arrive on the scene.

This guide has two main components:

• Information to help individuals learn how best to react, should they be caught in an active shooter situation.
• Guidance for employers to prepare staff for an active shooter situation, including creating an emergency action plan and conducting training exercises.

Source: DHS