"Y-Yeah... That's right, thank you for understanding, you see I suspected that Amelia is up to something so I brought those devices to protect us, but I didn't expect it to be that worst, I guess I've gone too far," Katherine lowered her head in embarrassment.
Aside from the lie about the device, Katherine really meant what she said about going too far in exacting revenge, she is ashamed of what she did back at the Mayor's house and to their other classmate. Only three of them were not unharmed that night which makes them a suspect and the subject of investigation.
While their classmates is taking a break to heal their wounds, their class is suspended for a week, this is also the way of the university to avoid being dragged in the current issue since the crime is done outside the school premise at in a private party, the school suspended the class so that the investigation will be done at their respective home.