>> but what they're about to record is their worst nightmare. eric is planning to rappel 300 feet into the beautiful but dangerous englesteed canyon. >> you can't really see the bottom of it. it kind of blows your mind away, just the scenery of it. >> they choose a spot and david helps eric set up for the rappel. >> i quickly noticed how tall, how far 300 feet is. i was very, very nervous. there are all sorts of factors that can lead to death and injury as you rappel. >> they seem to have all the equipment. except for a helmet, a key piece of safety gear for climbing and rappeling. david tapes as eric sets up for the rappel, checking everything twice. >> david grabbed the camera and tried to document the first rappel and the canyon was set up perfect because it was in a little horseshoe shape, so he could hike to the other side of the canyon. >> all right, man.