While POOH the 4th tubing joint and picking it up to cut the sucker rod, the tubing pushed the sucker rod clamp out of the string. The string was not secured anymore and slipped 0.5m down. The clamp was resting on the top of the tubing unsecured. While manipulating the joint, the sucker rod clamp slipped from the tubing, hit the elevator and bounced off towards Roustabout striking him on the right side of his helmet and then sliding and hitting him on his shoulder