Back to the video, what you saw happened strange as it was. The rider shouldn't have been there but was anyway. He isn't alone, lots of kiters find themselves in squalls, by accident, indifference or lack of appreciation for the teeth of the things. I sure as hell recommend against it, always, but folks will fall into it anyway by intent or accident at times.
Transitioning from kite low to the water to the zenith in stronger than gale force winds would be expected to send you flying. It is dangerous in short. The conventional wisdom is to keep your kite low, at the edge of the window and be ready to send the lot free if you screw up and are caught in a squall. Activating the IDS comes to mind again early. Parking it at the zenith usually would be expected to be a formula for a bad lofting but wasn't in this case, why not? Lots of questions worth discussing instead of flaming as in the other forum. I would expect different kites to potentially behave differently too. As Kent said a CB I might invert, I had one do that years back, pulled a corner out of the kite and bent a solid carbon bar (in clear gusty weather).
Here's another case, involving a 16 m BOW kite in a fairly weak squall, only gusted to about 30 mph. Lots of guys have been injured in killed in gusts of that speed, even lower so don't be deceived. Anyway, it struck him so fast, didn't push the bar out or Emergency Depower before the squall hit unfortunately, that he was climbing and well up before he really knew what happened. With a strong upward component varying the angle of attack of the kite doesn't do much at all. He kept going up.
Hanging out in squalls is a fools game, bad things will happen that skill and even great kite technology can't deal with. More than that we just screw up at times and fail to do the right thing. So, stay out of them.