The clip deals with the last 14 minutes of the trick, so I'm not sure what has gone before. Aya has apparently been tied down to a chair, put in a box-like room, the door blocked, and then the room put on a platform. As each minute goes by from the start one set of explosives goes off until three have gone off. Then there is an explosion on the platform and a fire starts; most of the platform collapses, hitting another contruction which also explodes.
Then the room that she's trapped in falls to the ground and there is yet another explosion. By this time the people watching are upset, the two women in tears, and Morning Musume, which has been watching this, is in tears, especially Iida Kaori. In the end, four men appear with a tarp and Aya magically appears under it (it is a magic trick, after all).
It's quite an interesting thing to watch.