So the opening cut scene in H5 shows Dr. Halsey with both arms so it was before the events of H4 Spartan ops. It shows her in what looks to be her office with what appears to be Cortana… But what I am thinking is that was a Cortana 2.0 so to speak. I have read that Halsey kept other AIs around in her office, even ones she wasn’t supposed to like Kalmiya(Cortana’s older sister). I am thinking Halsey knew that the original Cortana was going rampant and the events about to take place weren’t going to be good and no way would oni like another newer Cortana around and that is why she said that they would order Locke to kill them both. I was kinda thinking perhaps that ai we thought was Cortana was Kalmiya but Kalmiya was destroyed… Or was her memory simply erased while keeping her intact for Halsey to fix later and since she was supposed to have destroyed her that is why Locke would be ordered to kill them both…