Sana's shame: 1. Isak's blood is on her hands (literally) because she invited Elias and his friends to the party. Had she not invited them, Isak would not have gotten hurt, but she wanted to see Yousef so she invited them. 2. She knew about William's girlfriend but she did not tell Noora. Instead of Noora just being hurt by William, she feels hurt by Sana as well. 3. This is not Sana's fault even remotely but she is facing prejudice because of her religion and her family. Pepsi Max excluding her from the Russ bus and justifying it by shaming Sana for even wanting to be on the bus because she's Muslim. Also the strike on her appearance by mentioning the hijab in a negative connotation, but then praising Noora's beauty. Sana has to deal with the guilt of causing Isak and Noora pain, and also her relationship with God. She's already questioned her religion, and after being shamed by the Pepsi Max girls I'm sure she feels guilty about disappointing her God.