As for the fear of breaking things, that's where our old friend version control comes in. If you're worried that you're going to break the AI's code but still think it needs to be refactored, fire up your safety nets and go for it.
Maybe you'll break things, maybe you won't. Either way, you'll learn something about the code, make it yours in a way that just reading it and nodding along can't always provide.
I also did not understand the "fear of breaking something" bullet point. Why would that stop you from reviewing AI code?
You're right that version control is there to help, but it doesn't by itself stop you from pushing out broken code to production. That's the fear: landing bad code on user's machines.