The recommended action is Run, Hide, Fight.
If it is possible to flee the area safely and avoid danger, do so.
If flight is impossible, lock all doors and secure yourself in your space and attempt to barricade the door.
If you can do so safely, get all persons on the floor and out of the line of fire.
Hide behind or under obstacles and remain silent.
Attempting to overcome the armed subject with force is a last resort that should only be initiated in the most extreme circumstances.
Remember, there may be more than one shooter.
Wait for the “all clear” instructions from uniformed law enforcement authorities.
Be careful not to make any changes to the scene of the incident as law enforcement authorities will investigate the area later.