I knew you wouldn't listen to me. I just KNEW it. So instead of getting everyone captured, I sent a shadow copy of myself and stood by waiting for something to happen. I was right. There was no way you would have gotten out of an indestructible cage once you were actually in it.
(also, if it dropped from the ceiling, there is still nothing on the bottom of it, so if something really strong knocked it over, everyone would still be set free)