Almost finished. Lying on his back, hugging the end of the hose to his chest, he rolls his head from side to side until he can see the air vent that they picked out on the reconnaissance photos. It used to have a sheet-metal hood on the top of it, but that’s long gone now, it’s just a hole in the roof with a few jagged bits of metal at its edges. He crawls over to it and feeds in the end of the hose.