Complex sentence: Every show, Angier used the machine to create clones of himself atop the balcony, while unbeknownst to anyone, the original Angier would fall through the trap door to be drowned in the tanks under the stage.
Split into simpler sentences: Every show, Angier used the machine to create clones of himself. One would appear atop the balcony, while unbeknownst to anyone, the other would fall through the trap door to be drowned in the tanks under the stage.