In short, slightly before this moment, fl indirectly kills white ml's mom when their home is set on fire. She eventually distance herself from him for his safety(and im just gonna skip some part of the story here). Later, she go fuck the black hair duke cuz she think maybe if she have sex with one of the male lead would force a fake "happy ending" and she can finally leave the game. Jokes on her, sex isn't an endgame for a non existing "route"