Overview: At overwhelmed local hospitals, doctors triage the wounded, concentrating resources on treating those most likely to survive. The lobby of the Tropicana Hotel looks like a disaster zone strewn with concertgoers seeking shelter. Country music superstar Jason Aldean, his wife and band members are hunkered down in a tour bus now full of bullet holes. Meanwhile, the SWAT team does not expect what they find. As the nation seeks answers, the FBI joins the investigation.