My experience in a big Ontario teaching hospital and cancer centre is that if it's critical, they can move very, very fast — they'll basically sweep their arms across the table and clear everything else off the schedule for you (that happened for me repeatedly in 2021).

If they make you wait, the bad news is that you have to wait, but the good news is that they don't consider your situation to be critical.

If you think you're being forced to wait unnecessarily, every Ontario hospital is required to have a Patient Advocate or Patient Relations Office and you can reach out to them. If that's not satisfactory, you can escalate to the provincial ombudsman:

Email: patientombudsman.ca
Phone: 1-888-321-0339

(I've never had to do any of these things, but it's good to know they're available.)