ROANOKE, Va. A duplex explosion in a Roanoke neighborhood left one person in critical condition Friday afternoon.Roanoke Fire-EMS crews responded to the intersection of Dorchester Drive and Rutgers Street around 4 p.m. after the duplex exploded. When crews arrived, one side of the duplex was engulfed in flames and the other side had collapsed. Two cars were also damaged in the explosion.Residents described the moment the explosion happened."Big …