Saw it, and wow. I've done entry in two places that were as dark as that due to smoke. As Cluin pointed out, the stuff in the smoke is really nasty--many really toxic gasses come from burning sofas and armchairs. Only chance for people before the FD gets there is to get out by getting low--that is on ones hands and knees--and makin' tracks to an exit. When paint on walls goe alonw with other 'burnables' in the room, the temperature fairly guickly rises above 750 degrees. Unprotected humans aren't made for that kinda heat. The advice the film clip gives is great. Keep the tree watered. Or, better yet, get an artificial tree. Hope everyone has a safe and enjoyable Christmas.

Note too that the elapsed time in the clip was less than a minute. The quickest response likely from a FD is in the neighbourhood of 8-10 minutes. By that time, the room is engulfed and getting close to flashover--if flashover hasn't occurred by then. That house is not the place to be.

Great thread, Cluin.