Complex sentence: After Kirby answers Ghostface's questions she, believing she has won the game, goes outside to untie Charlie, but he suddenly stabs her in the stomach and reveals himself as Ghostface, before leaving her for dead.
Split into simpler sentences: After Kirby answers Ghostface's questions, she goes outside to untie Charlie, believing that she has won the game. He suddenly stabs her in the stomach and reveals himself as Ghostface, before leaving her for dead.