Beware of voice

An explorer in the deepest Amazon suddenly finds himself surrounded by
a bloodthirsty group of natives. Upon surveying his situation, he says
quietly to him, "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!"