He shoots at others but injures himself.
"Two injuries – a small bruise on his right arm and a minor injury to his buttocks – won Kerry his Third Purple Heart and a trip home. However, the vets say, the wound to his buttocks was self-inflicted and should never have received Purple Heart consideration. ... Larry Thurlow, an officer on shore with Kerry that day, insists the wound was the result of Kerry’s decision to throw a concussion grenade into a rice pile. The “shrapnel,” he says, was actually rice pellets."
He wants medals for self-inflicted wounds.
http://www.wnd.com/2004/08/26004/
even the beloved Counterpunch can't stomach Kerry:
http://www.counterpunch.org/2013/07/26/what-john-kerry-really-did-in-vietnam/