NORTH PHILADELPHIA (WPVI) -- An argument outside a North Philadelphia nightclub ended in a deadly double shooting.Gunfire was exchanged around 2:30 a.m. Saturday in the 3000 block of North 22nd Street.Two security guards witnessed the shootout and gunfire exchange between two people.And that's when they opened fire on the two people shooting.It's not clear if the shots fired by the security guards hit either of the victims.A 22-year-old man shot in the head.He was taken by a private auto to Temple University Hospital where he was pronounced dead.A second man was shot in the leg. He was taken by medics to Temple in stable condition.Officers found a third male victim a block away. He says he fell while running from the violent scene.He was taken to Temple Hospital with an injured head and leg. He is in stable condition, and is expected to be treated and released.The incident remains under investigation.------