When Dave and Prescott are fighting in the bunkhouse, Dave lands butt-first on the lit wood stove, shows no reaction to being burned, and there are no burn marks on his long johns. The stove is definitely lit. Flames are seen from a different camera angle.
It is very cold and windy, but when the door to the bunkhouse is opened, Dave, who is shirtless and near the door, shows no reaction to the cold.