Momentum can be a powerful force. All that bouncing a swinging just added so much load to the end of that boom. Looked like they should have went for smaller sections during disassembly. They would have had to break it down into smaller sections anyway to transport it. Now they have to cut it up even more <smirk>.
Hard to tell from our vantage point. But it looks like the guy on the tower might have needed to change his paints after the falling section missed the base of the tower.
I'll bet that crane operator was also maximumly stressed. Judging by the way the rest of the boom was whipping around, that operator was going for quite a ride in that cab.