I’m not sure how you could be waiting for PRcard with a visitors visa. I thought you needed to be a permanent resident before you get your card, anyways 1:if you are a permanent resident already and leave North America without PRcard you can not get back in to Canada(you can not get onboroad an airplain/ship from Japan or anywhere outside of North America) but if you apply/pick up a temporary re-entry authorization form (not sure about the exact name for it) from an embassy in Japan you can come back in. 2: pretend like you are a visitor then you might not have a problem at all but I would not try this method I think it’s too risky for you. 3: If you are not a permanent resident yet(in process of obtaining PR status) I think you can obtain a temporary re-entry authorization(nor sure about exact name for it) from an immigration office. 4: The best way to deal with this issue is to call the immigration office and explan your situation so that they can help you. I think because of your situation they may allow you to leave for compassionate reasons. Good Luck