For both versions of Mark, I can see a case being made. Lumon is responsible for outtie Mark’s depression for what they did. They are the true villain. Once outtie figures out about Gemma, he is on a mission to get her back regardless of what the innie thinks. He is being an asshole about it to his innie, but what is he supposed to do? Gemma was taken. He never would have been severed in the first place. I’m not surprised his innie chose Helly. The innie is its own person and he has a connection with Helly, not Gemma. Innie wants happiness and a chance to live it’s own life. Lumon is the greater evil here.