The Campus Slasher

I am a student. At 8 p.m. this evening, everyone in the entire school was pulled into a Group Chat. There are actually 14,368 people in the group. The Group Chat is named The Survivors. The limit for a Group Chat is 500 people, right? I thought it was some kind of sales group, but I can't leave this group. The group has been put on Mute All. In ten minutes, a Slasher will enter the school. No one believes it. But the number of people in the group keeps decreasing.