On the first couple views I thought it had a cut while they reset the room---then I noticed that when they do the coloured fluid opening the drape they're actually going down a shaft to a different floor, and you can definitely see everything set up if you look for it. I think this might have actually been all one take (there certainly are enough destroyed TVs in the background to make this plausible!)
I'm pretty sure it was all one take - most of their videos are like that. It may have taken multiple tries to get everything right ('Here it goes again', their most popular video with the treadmills, took 17 attempts, but they captured it all in one take [source:Wikipedia]).
No word yet on how many attempts this took - hopefully they didn't drop too many pianos
Wow.