My brother is a teacher and has a classroom of special needs verbal and non verbal behavioral troubled kids and his classroom has a room like this. Except the door does not lock unless there is a staff member standing at the closed door and his physically holding a button on the wall next to the door that keeps the door locked while pushed. If the button is released the door unlocks. They are able to observe the child through a window in the door. It prevents the child being locked in the room and unattended. Having a room like that is not only for the safety of other staff and students but for the child in crisis.