It is still easier to revoke your PR when you are outside Canada. When you show up to the interview, they can yoink your PR card and you will be outside Canada without a way to get back. If you try to apply for a travel document, they can refuse based on that you do not meet the residency requirements.
If the interview was scheduled inside Canada, they would have to give you an order to leave which would turn into a deportation order after some time but it would be easier for you to fight it if you are in Canada.
However, I really hope they are not going to do that. When you sponsored your children, you had no other choice than to apply outland where your kids live. Sometimes they call for an interview because of spousal cases but I have never heard of a sponsor being asked to interview overseas. I have also never heard of an interview to sponsor minor children. It's not like a spousal case where you have to prove that the relationship is genuine. They are your kids, says so on their birth certificates I assume.
I hope the best for you but if they do yoink your PR card and leave you stranded in your home country with your kids, don't be too surprised. Also if they don't take your PR card, go back as soon as possible in order to continue to fill your residency requirements.