As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PAX TRAPPED IN LAV, ABLE TO OPEN DOOR AT FLIGHT LEVEL 210. ( LAVATORY WASTE SYSTEMS - LAVATORY UNUSABLE ). REMOVED FROM SERVICE. REMOVED AND REPLACED LAV DOOR KNOB LATCH ASSY OPS CHECK GOOD NO FUTHER DEFECTS NOTED. CLEAR MEL. AIRCRAFT RETURNED TO SERVICE.