He used it in the first building. He also put cinder blocks around his fire, to reduce the direct light from the fire, and wet cardboard on top to absorb the smoke. No mention I don't believe of where the precious water or wet cardboard came from.

If Discovery Channel/BBC didn't already own "Man vs. Wild", they could have appropriately labeled this "Man vs. Wild: Apocalyptic Edition". Why risk killing yourself jumping across voids? Me, I personally enjoy the thought of lying at the bottom of an elevator shaft enjoying a slow painful death!