ACTUALLLY, the drummer doesn't knock over the overhead mics...the guitarist goes way wild on his lead/solo deal, jumps up on the riser, and gives it a good shaking, which knocks over one mic, and then during the break, the Fabrizio gives a four click intro on the stand, which knocks it off the riser, taking the other mic with it. If you listen closely, you can hear a big difference in the toms and cymbals before/after the mics go "boom"
I love that video