Trevor Ault reports on the Southwest flight that violently dropped hundreds of feet, throwing passengers from their seats, as the pilot tried to avoid a midair collision with a military plane; Pierre Thomas has the latest on the deadly shooting at a University of New Mexico student housing complex after authorities in Albuquerque arrested a suspect; Martha Raddatz reports on the growing hunger crisis in Gaza as ABC News cameras go inside a pediatric ward in the war-torn region, where children