Alright, I'm certain the spoiler warning for this wore off anyway. In the midst of thinking about spoilers, I was just thinking of the big "Oh no, Sentinel killed Ironhide" thing. But then the thought occurred to me, why did Sentinel kill Ironhide in the first place, right then and there? All he was doing was explaining his motives, and Ironhide made no first move or anything. Did he see him as a potential threat? Or did he just shoot him in the back because "I'm evil now"? I mean, he tried to appeal to Optimus to have him join them, why not do the same with Ironhide and the others?