Spoiler: The finale was suppose to end differently...

Rue relapses. Yes, it's a relapse because her makeup is the formal makeup. But I think she dies in her bed.

Hence her body lifts the way it does, the only person to interact with her in the kitchen is her dead father (u/frontsnapkick2urface mentioned it in a comment), and the song ends with "when I disappear into that good night."

But it got renewed, so they added the voice saying "until then," imply she survives. Just my thought.