THE PNEUMATIC GREASE PUMP WASN'T WORKING SO EE WAS TRYING TO SEE WHAT WAS WRONG. HE TOOK THE PUMP COVER OFF AND HEARD AIR ESCAPING. HE PUT THE MIDDLE FINGER ON HIS LEFT HAND INTO THE PUMP BODY TO FEEL FOR AN AIR LEAK. AS HE DID THIS, THE PISTON WHICH WAS IN A RAISED POSITION CYCLED DOWN AND CUT THE FINGER OFF AT THE FIRST JOINT FROM THE FINGER TIP.