If your medical is already expired and you have not been asked for a re-med, then that means your visa office has decided to extend your medicals.
Also if you get PPR a day or two before your medical expires, your visa office will give you an extended time to travel.
In both situations, your visa office will give you enough time to travel and this time cannot be determined by us but your visa office.
However, you do realize that the scenarios you have laid out are 1 / 100 lol.
I have given you the basic guidelines of how the dates are determined on when you can travel.
All this information that I am quoting is from other forum pages and experiences with past people including me.
I hope this information is helpful. Have a nice day