EE WAS USING 3/8"" DRIVE IMPACT TO REMOVE BOLTS FROM GAS TANKS STRAPS FOR REMOVAL OF TANK. BOLT HE WAS LOOSENING WITH IMPACT WAS SLIPPING. HE THEN NEEDED A WRENCH TO HOLD THE BACK SIDE. HE PLACED OTHER HAND ON BACK SIDE OF BOLT TO FEEL WHAT SIZE NUT IT WAS. AS HE PLACED HIS FINGERS ON THE NUT HE ACCIDENTALLY TURNED ON THE AIR GUN SPINNING NUT CUTTING FINGER.