A lockdown may be instructed during situations such as the presence of a hostile or armed intruder inside a building. A lockdown requires locking doors, windows, and barricading oneself to block entry to a campus facility, a classroom, or to an office suite. The term lockdown is often confused with "Shelter in Place".
Due to the varying levels of construction and architectural design of the buildings on campus, one classroom or office may provide more or less security than another. Interior walls built using steel, concrete or brick will provide more cover than ones built using sheetrock. Inward opening doors can be barricaded to prevent intrusion whereas outward opening doors cannot. Solid core doors provide more concealment and protection than ones that are hollow or ones with windows.
If you are unable to immediately and safely escape, then lockdown in the nearest safe classroom or office and deny the assailant access. Lock and/or barricade the door. Whether the door has a lock or not and the door opens in, a good heavy door wedge can be kept on hand and driven in as hard as you can, then use all available heavy and large items in the room to barricade the door.
Move to an area out of the field of fire should shooting through the door occur. A single desk or chair will likely not prevent the penetration of most bullets, although several strategically stacked tables, desks and chairs may lessen the velocity of a bullet, thereby lessoning the potential for serious injury.
Make the room as dark as possible; remain calm and be as quite as possible. Silence all electronic devices that may alert the assailant of your location.
Do not open the door for anyone except for identifiable Law Enforcement personnel.
Depending on the assailant’s location, consideration may also be made to escape through window openings. Have someone watch as you get as many people out of the windows as calmly and as quietly as possible. It is not recommended to escape through windows above the second floor; even jumping from second floor window heights may cause serious injury.
While in lockdown, if there are injured persons treat their wounds. Remember basic first aid concepts. If a first aid kit or bandages are not available then improvise by using any available resources within the room.
Formulate a plan of action with the people in the room should the assailant breach the door and enter. You may need to counter the assailant’s actions and defend yourself. Locate any available objects that may be used as diversionary devices or weapons.