>> all of a sudden you hear this big bang. all performers completely just froze for a second. we were waiting thinking it was planned, but it wasn't. you hear screams everywhere. >> i knew something had gone wrong. that's a ten foot drop underthere. i was in shock. >> at a news conference it was stated stage maintenance is turned over to investigators. >> there's a cover there. it appeared the cover collapsed in total immediately. >> audience members and school staff immediately began rushing the stage after the collapse pulling the teens to safety. >> all the debris wood and everything were covering students. people just jumped down trying to lift. a terrifying site to see. >> authorities say more than a dozen students were injured, all taken to area hospitals with