She does believe him, but also she can't help but feel angry and sad and hurt and full of guilt at the same time. Don't blame yourself for other people's actions, don't blame yourself from what other people do, but she can't help it. And maybe she feels worse because it was easier when she blamed herself than when she had to accept it wasn't and Megatron is at fault and she can't just be better and he'll be better because she fixed it. She can't fix this, only he can.

"It's always too high," she says. "You...You get mad and you think you're protecting people, the people you love most, but it goes wrong, because you getting mad means you didn't think it through and a lot more people get hurt. Especially the people you love. I learned that myself. But you can't say mind control made you do it like I can."