All I know is that when I saw the bathtub scene where she grab Mrs Shizuka's breasts and the rei hugged her that she cares about her and that got me wondered if Rei loved Mrs.Shizuka? If that happen man that turns me around cause those two would've been a great couple in the apocalypse.
This event is too far from happening. Have your teacher ever praised you? It felt good right? What if you are a close-friend with your teacher? Thats their relationship. This means Rei, who is utterly obsessed with her childhood friend Takashi whom she can never remove her romantic feelings even if she had a boyfriend, can never be inlove with a woman.