>>30431427She wanted a chance to talk back to her mom, something she's never had the guts to do before. She told you multiple times through the story that the reason she wanted to save was so she could "tell her something", which turned out to be telling her how horrible of a mother she was. It just so happened to end with her fusing with Nihilego, attacking you and of course you having to defend yourself, and after defeating her it miraculously turned out that she wasn't evil afterall, but it instead was Nihilego who had poisoned her. Sooo, accidental save due to Lillie wanting to bitch for the first time in her life.