The rig crew had just finished picking up all riser from the outboard riser bay. The gantry crane proceeded to transit from the outboard bay to the inboard bay. In preparation to pick up the first joint of riser from the inboard bay a Roustabout was working from a scissor lift located on the aft end of the inboard riser bay. The
scissor lift toppled over when struck by the gantry crane and the employee rode the basket down (approximately 17 feet) to the deck. Employees medical condition was stabilized and he was evacuated by medical helicopter.