In my case, I didn't do the medical exam up front, so when I got my work permit it stated that I wasn't allowed to work with children (like at a school or in child care) or in healthcare services. Since I previously worked in the medical field before moving to Canada, it meant I was still unable to look for a job in my field. My options were to either wait until PR went through, or to go do the medical exam (before the government officially requested it) and then reapply for a work permit and pay the $255 again to try to get a work permit without the restrictions. In my case, it wouldn't have really been worth it to try for another work permit, because it could have taken up to four months plus however long it took to get the medical exam done, and I ended up getting PR right around the time I would have gotten a second work permit.