Sleeping with your door shut can give you up to an extra fifteen minutes to escape a house fire. Having the door closed prevents smoke from readily entering your bedroom and acts as a short term barrier to the fire. In a fire situation, if you cannot get out the door, go to the window and yell or hang something out the window to attract attention. Additionally, placing sheets, towels, clothing, etc. at the bottom of the door will aid in keeping smoke out of the room while you are at the window awaiting rescuers.