I probably should go to sleep now but I just realised something, was Sua ever scared that Mizi would find out? Sua dedicated her entire life to protecting Mizi’s innocence and followed that to the end of her life. Mizi’s pureness and optimism was what gave her an escape, thus becoming her obsession (as stated in the art book) and it is through her own selfishness that Mizi collapsed when faced with her first encounter with loss. She took the easy exit so that she doesn’t have to face the reality where she no longer has the escapism she found in Mizi’s innocence, so was she ever anxious that Mizi would lose the innocence before due? What if Mizi encountered such a loss before Sua was ready, thus taking away her obsession, her reason to live?
I feel like in a universe where that happened, Mizi would still collapse from the long time she was protected, but would adjust better and therefore making her stronger mentally, though how she’d react after knowing the truth of the stage I can’t say. However, I think in such a universe perhaps Sua wouldn’t throw her life away so easily, and would actually try to win.
Still, Sua’s obsession really does leave room for such interpretations. Since Sua is, y’know, dead, we really don’t ever get to see her perspective of things. Of course, there’s the “where else would I find such a heavenly garden” comic and that comic of Ivan calling Sua out, but an obsession is much more complex than that. It’s not just love, but selfishness and hatred and every emotion imaginable.