I am confused as to how this could happen.

I thought that if a flight between 2 Canadian cities, continued on to an international city - then all the ongoing passengers to the international city had to disembark at the second city, and then re-embark - I assume that this is a Canadian customs regulation - that is what happened on my flight from Toronto to Vancouver a few days ago - that flight went on to Hong Kong.

If all passengers have to disembark, then obviously, then the AC flight attendants would have had to awaken her up. Or in St. John's, on this flight, the ongoing passengers (to LHR) do not have to disembark?