For what reason does Amal enter the women's restroom at the start of Chapter 11 and how does Tia react when she enters the restroom?

In order to prepare for fajr, Amal goes into the restroom at the beginning of the lunch period to perform the rite of "wuduh," (117) which involves washing her feet. Tia comes into the restroom with one of her friends and begins to make fun of Amal.