Chad, Cameron and Gabi are all leaving so it must be one of them. My guess is Gabi. Maybe she’ll get killed and everybody will think it’s Nick and it may be somebody who wants to frame him; somebody from his past who wants to settle an old score with him. Or, if Nick is leaving, maybe he will kill Gabi in his obsession with her. Just wild guesses on my part.
I would LOVE it if it was Anne or Theresa since I can’t stand either one of them but I’m sure it won’t be.