Heading straight for a rock wall along New Zealand's Waimakariri River Gorge wouldn't normally faze Shaun Baker. But this was a new experience even for the world-record-holding waterfall jumper-this time his kayak had an engine in it, skipping him like a stone at more than 30 mph. Finally he backed off the throttle just enough to steer himself parallel to the wall and avert disaster, before gunning it back up to full speed.