To understand this I think we have to look back at the intro of Halo 4. We never discovered the identity of the man who was interrogating Halsey, and even though it seemed like he was asking about how to create new spartans(which he was) i had a thought that maybe he wanted to know Johns weaknesses so they could prepare to defeat him. Why would they want to do that? To use their new Spartans to eliminate John and show their strength. But ONI would need a reason to kill him right? This is probably unlikely, but what if Serin Osman sent Palmer to kill Halsey, knowing Lasky would try to protect because if you know someone as well as she knew him, you can predict their reactions to certain things. She knew Halsey would survive and try to get revenge in the UNSC which is where John begins to become unsure of his allegiances. This is first shown in Halo 4 when he defies Del Rios order to hand over Cortana, choosing his only friend over the law. Imagine a similar scenario in which John is surrounded by spartan IV's and has Halsey, his mother figure at gun point. I could definitely see John fighting against ONI and the IV's and it would also be interesting to see Lasky and some Spartans(IV's and hopefully blue team) go rogue with him based on trust. The quote that I keep thinking of is "You say that like soldiers and humanity are two different things. Soldiers aren't machines, we're just people." In case you didn't understand my really confusing writing(which I apologize for) I want to see Chief, Halsey, Lasky, Blue Team, and some Spartan IV's fight ONI