Two scenarios - 1) a Canadian in the states: The American medical system including all varieties of insurance is a mish mash of craziness. So when a Canadian has something serious and has any kind of ambulatory ability, they will board an aircraft and fly home. I've worked in hospitals in Illinois, including working as a student while working at Pres. St. Lukes..... Medical Center in Chicago in the finance and collections area. Canadian hospitals don't have a collections center, this will give you an idea of how different the systems are. In Canada, you don't require one. My BC medical insurance will cover much of what may happen but third party insurance is highly recommended to cover the rest. This insurance may not be cheap or even available if you have some wretched condition.
2) Americans in Canada. Because of a plethora of insurance types and coverage, your out of pocket experience will vary. But, we have an excellent back up personnel to get your "^ss" out of a jamb. So lets say you are in the Broughton area and you end up having a stroke, for example. What will happen is your Mayday call will be dispatched out of Victoria. The dispatch will contact Canadian Air force Search and Rescue [Comox] and a helicopter will be activated. American military Search and Rescue envy Canadian military Search and Rescue because the Canadians have the jurisdiction to rescue civilians. I learned this based on a conversation I had with a Navy type out of Oak Harbor Naval Air Station.
If I were issuing a Mayday call in this scenario, I'd request a "Mayday relay" to ensure that Victoria received the call. There are marine radio repeaters along the BC coast so the relay may not be necessary, but I'd still do it to ensure reception by Victoria.
The flight from Comox to the Broughton area wouldn't be that long.