The big sister wonders why she didn't give her son more time to prepare for the forbidden battlefield. She thinks that if he had been a few days behind, he might have been ambushed. She also thinks that the demon who entered the academy should have at least been in the "true essence realm" so that he wouldn't have to deal with the xias' goons. In other words, she thinks that he would have been able to destroy the demon with just the "primal breath realm" . The big sis thinks that she can use this as an excuse for kicking xia out of the school.