This is a cool prank and all, but I really do not think I would be messing with a machine that can take a metal screw out of your body like a person taking a thumb tack out of a bulletin board.
Yes, I realize the guys in this video aren’t in any danger (unless the guy putting the metal block in there had a wrist or arm screw), but still; that is just not the kind of equipment I would ever mess with.
I am also wondering where these guys are and how much trouble they would/will get in for messing with a machine that costs thousands of dollars…