hand foot major wound knockdown stunning

[DouglasCole]

People have been known to fall down when MISSED at close range with gunfire. It was a psychological reaction to the expectation of pain on being shot. Basically, a failed Fright Check.

With a REAL harpoon sticking out of your hand? Yeah, what GURPS calls knockdown (and certainly stunning) is quite possible.

You might scale it, though: A failure by 0 means you are stunned but stay standing, a failure by 1 means you drop to your knees, 2-3 you drop to crawling or sitting, and 4+ you fall all the way to lying down, either face-up or down.