Outbound Immigration
Once you are checked in, you can move through to the outbound immigration area. There is usually a multitude of retail and food outlets prior to going through outbound immigration area. You will most probably want to get through immigration and into the retail/food outlets or the airline lounge/club on the other side of immigration as quickly as possible. This is a best way to ensure you are on time for your flight. Immigration lines can be very long at peak times and are variable so best to pass immigration quickly. You never know how long they will be until you arrive.
Once you have been through outbound immigration, you have technically left the country.
Remember you will not be able to go back. The check-in and your car will be off limits so make sure you are ready to leave the country when you go into the immigration area.