What with Nikaidou suddendly calling Tadokoro by Kageko ?
I recall she also temporarily switched to "Kageko" when with Tadokoro's mother (who also answers to "Tadokoro-san").
As for Chapter 47, I'm willing to bet that it's a dream of some kind, given that not only does Nikaidou call Tadokoro by her first name, but she shows up in a limo (which Tadokoro thinks is out of a movie), and there's a sudden overtly romantic atmosphere without any buildup whatsoever.