Escape if you can.
If possible, help others to escape. But remember, your own safety comes first.Do not expose yourself when escaping - duck and be inconspicuous.
Warn others in order to prevent them from entering the danger zone.Lock and barricade the door.
Turn off the light and silence your phone (sound and vibration).Move away form doors and windows, and lie down on the floor.
Or hide behind substantial brickwork or a heavy reinforced wall.Call the police: 117If fleeing towards the police: do not run towards them and avoid hectic movements.
When the police arrive, hold up your hands an show your empty palms.