But I Cant Go

Its a normal day what could go wrong? You would think nothing. Kids are just at school when the suns out and its anice day. But all of a sudden the sky darkens the air fills with helecopters. Somethings wrong. The school goes into containment. They think its no biggy. Until pounding hits the door and the annoucer disapeers. There in lockdown and then the school is screaming.