 Singer employed his friends in the tunnels as his crew. Singer  claims that these people, with no prior experience in filmmaking  whatsoever, were incredible in their ability to set up lighting  rigs, dollies, and electrical wiring, mostly without the use of  tools or real grip equipment. To make the dolly for tracking shots,  Singer and his carpenter built a rig made out of wood and metal  scraps. Without a power drill, they would heat a metal rod and  singe a hole into the wood to put a screw or dowel in for fixture.