(You're Mizuki)

Because Mafuyu Asashina manages to talk with her father about her emotions, she wanted to talk with someone too.. And why not say to Ena that she is actually transgender, the worse she can do it ignore her! Right?. She told Ena too meet at the rooftop of the school. When Mizuki came there she heard Ena talking with some classmates!.. About her being a dude before. Mizuki opens the door and looks terrified she couldn't say anything and quickly ran away, she could face Ena at this point.