Thank you for your kind words! At the end of the day, it's about whatever you think it's about, but I'll tell you a little bit about what I was thinking.
The game is very autobiographical in that I have a lot of health issues and more than a few hospital stays, but the purpose of the second night isn't to give you information about Elly's past: It's to give you information about what's wrong with her through allegory.
The theme of the second night is "You should be able to count on this thing to take care of you, and it can't because there's something wrong with it." - A nasty autoimmune condition like mine is a lifetime of "Can my body resolve this issue on its own? Or do I need to step in with medical intervention?" That anxiety is the basis of the horror in the second night.