hello Chobee
I passed for your same situation, with the difference that my work permit expired before got the Medical request. You should renew your work permit, it is very important that you keep your status while you are in the process to get the PR. As you were approved for the AINP, you won't need a new LMO, so the process will be easier for you.
I suggest you to start the process to renew your work permit because we are not sure where exactly we will receive the PR.
I am just reading in another forum that Buffalo sent a letter to a guy requesting for proof of his status in Canada because the work permit of this guy expired in the past february (as the mine), this guy had started the process to renew one month before it expired, he is ok because he has a proof that his status is the same and he is waiting for new documents. After read about this, I will send my new work permit to buffalo, just to let them know that I have renewed my documents and I have the same status.
Hope this helps you,
Johanna