The season finale is the episode after the next.
They did not kill either character for the DUI reasons, and they almost changed the plot so people wouldn't think that--but ultimately decided against letting real life events effect the plot. Michelle Rodriguez only signed on for one season because she's got movies to do and stuff. The writers felt they would shortly run into a brick wall plot-wise with the Libby character, and feeling that having a love interest for Hurley was not enough of a reason to keep her around, they decided to have Michael kill her as well, in order to make the event more shocking and tragic for the audience (who were more sympathetic with her than Ana Lucia.) Again, she will be a guest star in flashbacks in season 3 where the story they did have for her is intended to be told posthumously.
They did not kill either character for the DUI reasons, and they almost changed the plot so people wouldn't think that--but ultimately decided against letting real life events effect the plot. Michelle Rodriguez only signed on for one season because she's got movies to do and stuff. The writers felt they would shortly run into a brick wall plot-wise with the Libby character, and feeling that having a love interest for Hurley was not enough of a reason to keep her around, they decided to have Michael kill her as well, in order to make the event more shocking and tragic for the audience (who were more sympathetic with her than Ana Lucia.) Again, she will be a guest star in flashbacks in season 3 where the story they did have for her is intended to be told posthumously.