He should'nt do that. He needs to first blow up both his leg by shooting at it's kneecap. If possible, you need to keep him alive by making a tourniquet on the amputation stump, pumping enough blood and an oxygen mask so that his brain keeps being oxygenated and is'nt really damaged.

You need next to break each one of his fingers with the butt of the rifle. just take a few minutes for each, they need to be purple and completely mishappen because of the several hematomas inside. If there are no more fingers, proceed to skin his forarm with a little cut of 1 cm of depth and pull the skin backward slowly so that the skin does not tear off.

Finally, take a botomless birdcage, a rat, a torch : Put the rat in the cage against his womb and approach the torch. The rat will be scared of the bright light and will dig a path to hide deep down his intestines.