No, you will not able to do that. If you want to leave the airport for few hours then you have to go through customs/immigration at NRT, just like international arrival at the U.S. Airports. If you want immediate access to a lounge, then you have to go through transit process and head to departure gate area where lounges are located.

Japan has a passport control for departing international passengers. Once you made it to the departure lounge area, then you cannot walk back to check-in area and leave the airport like you can do at the U.S. airports.