Honestly, I'm curious exactly what sort of deal with the devil she signed that makes her unable to quit. I mean the job paying for her education seems the most logical guess I've heard but she's like 30 right? How long does she have to work for these people before she's paid her due, 5 years, 10?
Edit: Just had a thought. What if Fishman (generously) paid the school loan off or something. I mean if she's gonna pay someone off through working a job it might as well be Sakana she owes, then at least she'll stop being so held back streaming. Not that Sakana would ever do something like that, it's just a thought.