The way the over-the-top imagination sequences in Nanami’s Egg reveal how terrified Nanami is of being seen as subhuman retroactively makes the sequence in The Cowbell Of Happiness where Touga treats her like an animal to be slaughtered (as a metaphor for the way he’s grooming her into his own Anthy) even more horrifying.
Or, possibly, Nanami’s oddly specific “being treated like an animal” fears in Nanami’s Egg are because that dream planted in her mind the idea that somebody she loves very much sees her as more of a pet than a person.
Nanami’s fear of being abnormal probably comes from several places, not the least of which being that she’s obviously been demeaned for her oddities before (consider the adults’ disapproval when she shows up to Touga’s party with a stray kitten). But one of the most unsettling reasons is that she’s convinced that her abnormality will give people free reign to consider her subhuman.
Nanami wants to be loved, that much is obvious. But she also wants to be respected. Being loved like a pet or a toy isn’t enough for her. Above all else, she fears hatred, ostracization, and dehumanization. And that’s why she wants so badly to distance herself from Anthy.
Anthy is a Nanami given much more time to stew in her suffering. She’s escalated beyond just being dehumanized by others, and has started doing it to herself. She’s not an animal, though. That would imply some kind of life or desire or survival instinct, despite lack of sentience. Instead, she is a self-described “doll with no heart”.
It’s all a lie, of course, no matter how much she or anyone else believes it. Anthy is a person. She has desires and fears like anyone else. She can feel pain, even if she’s been steeped in it for so long that it’s become normal for her. She can feel joy, even if she rarely has reasons to. Anthy’s performance in the role of the Rose Bride requires her to cultivate a doll-like image, but she can’t cut herself off from her personhood completely. But still, she’s been so thoroughly stripped of her right to Be A Person that she’s stopped thinking of herself as one.
This was what Touga, and Akio, and the system of Ohtori itself had planned for Nanami. A cow to the slaughter, a doll in the making. And she obviously has a vague understanding that she’s in danger, even if it’s subconcious. But when she finds Anthy sprawled on that couch in the planetarium in the middle of the night, she finally, conciously, gets it. She finally knows why she was so afraid of being dehumanized. She finally sees the sword that she was sensing as it hung above her head. She sees where the road she’s on leads, and that’s all it takes for her to immediately do her level best to sprint in the other direction.
