Gee Doc's....your missing the point.
Any worthwhile EMS/SAR Captain will fly to a limit before he/she cancels any response.
And the decision to cancel will be aviation related only.......regardless of what type of medical situation he/she is going to..........it makes no difference.
You are suggesting that the worse a patient is......then the harder a Captain will push into the safety margins......come on get real chaps........thats a quick way to die.
Leave the aviation decisions to the Captain......unloaded by "PRESSURE" to get there regardless.......
As I said........I hope your Captains smile and walk away, disregarding anything not related to aviation.