I don't understand what's happening with people here. The guy has a PR visa, he is allowed to travel to Canada regardless. What does does non-essential, land vs. air, and officers mood has to do with anything?
Yes you can complete your landing in the 5 hours you will transit in Canada. No one will stop you. The airline will see you have a PR visa, CBSA in Canada will stamp your passport for landing ask you to isolate and at that point you will tell them you are flying back to the US and returning at a later time. If they ask why you did your landing now you just tell them you didn't want to have your PR visa expired and that you aren't ready to move now due to the whole situation.
So this thread/OP subject seems to have created some discussion but anyway the OPs original post proposed a US to US flight transiting Canada but unless I missed it did not clarify if by transit they had a single one way ticket therefore would be staying airside and be able to show this fact to CBSA.
By staying airside you could maybe assume that no isolation plan as a transit passenger would be required, however if the OP needs to go into arrivals hall and then to departures to checkin as opposed to transit connection for the US flight thus in effect entering the country that could be a whole different scenario coming into contact possibly with non travelling public.
Might assume it would not matter to CBSA whether minutes or hours exiting out of airside that they would not mandate an isolation plan with location/contact details as required for all arriving passengers as opposed to just actual transit airside .
Ultimately nobody here really knows any outcome given nobody here has any connection to CBSA or IRCC so there will always be a lot of speculation but hopefully if the OP does not stay airside they take the responsible path as mandated for arriving passngers.
Not a lot of point everyone going back and forth here on this, the OP needs to ensure they follow the guidelines responsibily or accept any consequences
