Bloodthirsty Natives

An explorer in the deepest Amazon suddenly finds himself surrounded by a bloodthirsty group of natives. Upon surveying his situation, he says quietly to himself, “I’m screwed.”
There is a ray of light from the sky and a voice booms out: “No you are NOT screwed. Pick up that stone in front of you and bash the head of the chief.”
So the explorer picks up the stone and proceeds to bash in the head of the chief. He is breathing heavily while standing above the lifeless body. Surrounding him are the 100 native warriors with a look of shock on their faces.
The voice booms out again: “Okay…….NOW you’re screwed!”