Oh, it was well choreographed. Notice that they start off with rubbing their hands together, then the finger-snapping, then thigh-slapping, then jumping on the risers, and then they back off to the finger-snapping again. The lack of synchronization between all of them is what really makes it work, as it sounds more like natural rain falling rather than a bunch of people making hand noises.
no subject
no subject
I suspect there's more than one kind of lack of synchronization. "Like rain" probably isn't the same thing as random.