What was found
(CAN) WHILE IN FLT, A PERSON WENT TO THE FWD LAVATORY, ONCE INSIDE, WAS UNABLE TO OPEN DOOR. DOOR HANDLE WOULD TURN, BUT DOOR REMAINED CLOSED. PERSON WAS BASICALLY STUCK INSIDE. CAPTAIN AUTHORIZED CABIN CREW TO USE CRASH AXE IN ORDER OPEN THE DOOR. FORWARD LAVATORY WAS PUT ON MEL. LATER, MAINTENANCE REMOVED THE DOOR AND REMOVED THE DOOR HANDLE MECHANISM. IT WAS FOUND THAT THE DOOR LOCK SLIDER PLATE WAS BROKEN, MAKING IT POSSIBLE FOR THE DOOR LOCK SLIDER LEVER TO COME OUT OF THE SLIDER LOCK PLATE, THE DOOR BEING IN THE CLOSED POSITION (SLIDER LOCK PLATE ENGAGED IN THE DOOR FRAME RECEPTACLE) MAKING IT IMPOSSIBLE TO OPEN THE DOOR BY ROTATING THE DOOR HANDLE. MX REPLACED THE DOOR ASSY.