I send an e mail to IRCC already to extend the dead line.I think you need to get permission letter but I don't know the exact procedure. its better if you can speak to police head quarters. I just called and clarified before booking the appointment.
I did Medical in Asiri Surgical and I live in colombo so I didn't face any issue while travelling. In your case, you may have to travel between provinces so it's better to check with them. Moreover, you have to inform the Canadian embassy about the delay. I think you should mail them today or at least by tomorrow.
You are very helpful.
Thanks.