Complex sentence: Meanwhile, the three kids decide to rob Bender, imitating his robberies on TV, not knowing that the safe marked "BENDER'S LOOT" was where Bender was sleeping.
Split into simpler sentences: Meanwhile, the three kids decide to rob Bender, imitating his robberies on TV. Unknowing that the safe marked "BENDER'S LOOT" was where Bender was sleeping.