A school lock down happens when school officials believe that there is a credible threat to student and staff safety. The goal of a school lock down is to keep students and staff safe, and while it may be frightening or disruptive, it is important to comply with the lock down for safety reasons.
When a lock down is ordered, people are told to stay inside their classrooms and lock the doors. This is designed to prevent entrance from hallways and corridors. Windows will also be shut, locked, and covered with blinds to obscure visibility, and people are often encouraged to stay away from doors and windows, sheltering in an area where they cannot be seen.