From p.36 "Unfit For Command" (First Purple Heart).
"The truth is that at the time of this incident Kerry was an officer in command (OinC) under training, aboard the skimmer using the call sign 'Robin' on the operation, with now-Rear Admiral William Schachte using the call sign 'Batman,' who was also on the skimmer. After Kerry's M-16 jammed, Kerry picked up an M-79 grenade launcher and fired a grenade too close, causing a tiny piece of shrapnel (one to two centimeters) to barely stick in his arm. Schachte berated Kerry for almost putting someone's eye out. There was no hostile fire of any kind, nor did Kerry on the way back mention to PCF OinC Mike Voss, who commanded the PCF that had towed the skimmer, that he was wounded. There was no report of any hostile fire that day (as would be required), nor do the records at Cam Ranh Bay reveal any such hostile fire. No other records reflect any hostile fire. There is also no casualty report, as would have been required had there actually been a casualty."
"You'll shoot your eye out!"