First you must acquire a V3S, try and have a passenger so you have twice the odds and a witness regarding your characters visible state. Then find yourself a hill (this was capture south of Berez and I imagine it works best with a rise in terrain as your target) and launch off it. The V3S should sink below the ground while your player cam rests on the ground. Now this is where Camrun (the ZAP member recording) relogs to escape the bug, but Mordon (also ZAP) gets out of the V3S.
In doing so he is left (until relog) able to move and harm players while remaining unseen/untouchable. He was not able to interact with items on the ground or in the vicinity.