A third possibility not mentioned is that if you transport by chopper you are presumably more likely to end up at a major trauma center rather than the closest trauma unit.
It's always been unclear to me whether you can/should ask an ambulance to transport a potential cardiac/stroke victim to one of the three major Boston hospitals rather than the local (perfectly adequate for most stuff) ER.
....And in related news, the New England Journal of Medicine published the results of another study showing strong indications that headaches can sometimes be relieved by aspirin.
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