I am a Pakistani doctor, having worked with the United Nations in Africa for a year. I have an official (service) passport issued by the government of Pakistan. I intend to visit Norway for about 8 days and I do not require any visa to enter Norway (because of the official Pakistani passport). I will book a flight with TAP from Accra (Ghana) to Oslo (Norway). This flight has a layover in Lisbon of 26 hours.
Would I be allowed to leave the airport and visit Lisbon during these 26 hours, or do I have to stay inside the airport for that period?
Should I get a visa for this stay in either case, keeping in mind that I don't have any Schengen visa?