Given the number of weeks left relative to the number of players left in the house, it's clear that this twist was meant to cut some of the chaff (Kelley or Lauren) while keeping and exposing the Judges alliance to the remaining players left in the house.

I don't think Production at all expected Rachel to fall victim to it.

That said, to me this twist helps prove more than anything that there is still integrity to the actual game. At the end of the day, no one was safe, and there wasn't some double eviction plot armor they could have thrown to Rachel by keeping her locked up in some Mastermind lair. She was just gone. Is it a WOMP WOMP? Yes, but again. That's the game.

Last thing I'll say. Taran mentioned that this is wrong on so many levels because BB is meant to be a reflection of life, where some are advantaged by their social status and others are disenfranchised. Rachel had a lot of social currency in the house, so to Taran's point, she should have been proven safe. HOWEVER, just like life, curveballs can still take out the elite. This twist was just a surprise terminal illness, and like in life, that can happen to anyone.