OHIP covers you for emergency medical care and transport back to Canada (not perfect but better than nothing)
For people travelling outside Canada, the ministry pays a set rate for emergency health services. Emergency health services are those given in connection with an acute, unexpected condition, illness, disease or injury that arises outside Canada and requires immediate treatment. Ambulance services are not covered. Ontario residents are encouraged to purchase supplementary insurance when traveling outside Canada as many emergency health services provided outside the country cost more than OHIP may pay.