Ahhhh, this is a good idea, but also, consider! OP is mutilated, and Sentinel goes on his merry way, complete with hands and a face. Optimus has taken the fall for him in a bigger way than just getting stuck with a shitty assignment, he’s lost his face, and it was all because Sentinel threw him under the bus, but he wouldn’t throw Sentinel under the bus. If Sentinel remains stuck in his land where he has to believe that he’s right, and that everything went wrong because Optimus screwed up, then good! This is vindication! This is just! This is the punishment Optimus deserves, even if he got things to that point by not being entirely truthful. Every time he looks at Optimus’s face, it’s validation for his feelings. And every time he feels those emotions, it’s validation for what happened to Optimus’s face. A nice ugly feedback loop.
And then! When he gets to Earth and sees what happened to Elita, I mean. We’ve seen canon, it horrifies him. His reaction to anything organic edges me pretty close to being willing to straight-up call it a trigger, and what happened to Elita because he screwed up– because Optimus screwed up, given the emotional trauma he took away from the incident, from his point of view, it is LITERALLY the worst thing that could have happened to her. Seeing how bad it is, that’s maybe even a shock strong enough that the blame-to-be-assigned overflows from ‘just Optimus’ so that the thought starts to creep in that maybe, possibly, it might be a teeny tiny little bit his fault that he pushed them to go to this planet in the first place.
And after that, every time he sees Optimus’s face? It’s awful, but it’s a just punishment. It’s what Optimus deserves. For that thing that was… maybe Sentinel’s fault. That he never got punished for. That Optimus got extra punished for. But– but no, if Optimus hadn’t messed up, Elita would have been safe, and everything would have been fine. And what happened to her was even worse than he could have guessed. So Optimus extra deserves this. Even though. Sentinel maybe deserved. A little punishment. Maybe. And after all that, after ages of having to believe that this is Right, he’s reminded of all all those doubts every time he looks at his two old friends and sees what happened to them. Every time he sees them, he’s reminded that he’s the only one who came away from that situation intact, all for something that he can maybe, quietly, admit in his own head… was actually his fault.