it's a remake of a public announcement aired in NZ exactly 10 years from when this one aired, also called "The Speed of Fire" where a woman smoking on the couch got up to do something and left her cigarette on the couch, cuts to an ad and the fire starts, a few more ads and brief cuts and the house is burnt to a crisp. The effect of the ad breaks is it actually simulates the real amount of time it would take to go from one cigarette to the entire house burning down (about 2 minutes, 40 seconds.)