In this video Chris Burden asks a friend to shoot him. He is trying to make a point that was relevant during the Vietnam War but also applies to other instances where people use guns. This performance piece is very much in agreement with the postmodern idea that art should make us think.
Burden is trying to shock the viewer, to make people think this is was happens in a war everyday. He is also looking for a reaction: "could I have stopped it"? "Maybe I should have stopped it." The hope would be that this reaction could be extended to stopping the war.
It also raises the question about the legality of the voluntary shooting. I wonder if his friend got in trouble for shooting him.