I know a couple for whom serving in Bethel was their one and only ambition, the only goal that they had in life. They got accepted.
A few years later she developed lupus.
That sounds a lot like my brother and his wife. My brother had been at Bethel for 6 years when he was allowed to get married and bring his pioneer wife to Bethel. They were there 12 years before she developed lupus and they had to leave. I never heard the details from my hard-line company-man brother, but he made it sound like it was their decision. They ended up moving to Maui, which is where she is from.
My brother had risen far - Bethel elder, running the water treatment/sewage treatment plant at Watchtower Farm, so I never thought that he would have been asked to leave. They'd invested a lot of money and training in him for classes and certification. Then again, she couldn't physically cope with her housekeeping job. In fact, I remember visiting them, and she took a nap instead of eating lunch. She was fast becoming dead weight.
Knowing what I know now about the coldheartedness of the Society it seems more likely to me that they were given the boot. Little bro is still staunch, an elder in his congregation, but I haven't seen him or spoken to him in 9 years, so I don't really know.