If you consider an accident on the M25 Sean, with the motorway closed to allow a medivac helicopter to land. That's going to delay more people and for longer than the circumstances last night.
(If there's a police helicopter chasing bad guys near the M25/M4 that would be another occasion to delay your departure.)
I think the reason "one femail controller got her knickers in a twist" was perhaps that she got fed up with being questioned? As your post shows, airline pilots aren't used to giving priority to non commercial flights?
However, I can't begin to speculate on the circumstances that would require a search and rescue Sea King to pick someone up off a flight at Heathrow and take them to hospital, they must have been in really bad shape. DOes anyone know the story?