Door issue aside, this flight could not have continued to HKG because Goose Bay has no ETOPS-qualified B-777 mechanics to inspect and release the flight. Goose Bay fuel would not meet UAL's fuel freeze testing requirements for polar flights. For these same reasons, the "rescue" 777 had to return domestically to Newark. Reports are that the passenger in question walked out the door and down the stairs to his medical escort. Poor choice of airports for a medical diversion, better choice would be Gander'St. Johns, Newfoundland or Keflavik, Iceland. Chances are also good that the aircraft did not dump enough fuel to avoid an overweight landing, another lengthy inspection requiring qualified mechanics. Captain made a bad decision or got himself talked into one.