Girl did we even read the same thing? Pretty sure she wanted to be with Shinpei but realized it's destroying him so she "wants" to give up. She probably had other plans but with how Shinpei is right now of all it isn't coming to fruition. Let's not forget the matter of him killing, she didn't ask for that but he did it despite Satoko telling him she doesn't like it. They have clashing morals that happens, Satoko is probably having an inner turmoil we're yet to find out. The chapter literally shows that Satoko is the type to worry about everyone, I'm talking about her concern with triplets knowing what Shinpei is capable of. I'm sure it's heartbreaking for her to witness her lover turn into a monster, remember she didn't fall for him when he was acting like he was now she fell for him when he showed he was human.
I was gonna address this but was too lazy to type out a paragraph, I was just mad atm
she is reacting reasonably what
Stoko PMO, she had no problem using him when she wanted to escape but she feels different now?