Operations were in progress to retrieve a storm packer set at 364’ RKB with 121 stands 5” drill pipe hung below the packer. The storm packer-retrieving tool was made up to the first stand of drill pipe and three more stands of drill pipe were run. The forth stand was lowered until a single was above the rotary table and landed on the slips. The backup tongs were placed on the tool joint to back up the make up of the top drive system (TDS). As the TDS connection shouldered, the tongs bit and then momentarily released and immediately bit again, causing the 1” snub line to “whip” and strike the Floorhand on the back left side. The Floorhand suffered 4 cracked ribs, a bruised lung and kidney and a lacerated spleen from the snub line contact.