In our school, they actually make an announcement to say that the school is in lockdown and staff should follow the instructions in their emergency handbook. The handbook is located in every room in the school and instructs staff to pull any students in from the hall, lock the doors and move to an area of the room that cannot be seen from the door or windows if possible. All of our doors and windows have blinds that are to be closed during a drill or an actual event. Once the event is over, another announcement is made.