What surprises me with everyone now having a camera in their hand is why this sort of situation has taken so long to actually occur and why protocols to protect the airline were not drawn up for circumstances like this. Image if this was someone returning for a funeral/end of life situation being asked to miss a loved one slipping away?
The second thing is why did security went all ballistic initially? There are a number of basic methods including non-confrontational/physical methods. I would expect a pub bouncer to have more acumen than those who perpetrated the alleged assault on the Doctor.
Finally, as this was spiraling out of control, where was the voice of reason from a senior ground crew member? Phones recording the carnage everywhere videoing a paying passenger bleeding, being dragged from the plane... what could possibly go wrong?
From what I can see is that there are too many people with the word "security" in the USA not adequately trained in avoiding conflicts and that UAL have some serious issues with how they manage risky situations. Chartering a six seater aircraft and a taxi fare either end, may have saved the airline and the bosses job. I've never had a bad experience with United and wish the staff all the best but please grow some cojones when it's going tits up.