The Restricted Zone is the zone where the Restricted Laboratory is located. It can be accessed near the bottom of Sector 6, with a shutter blocking the entrance. The first time Samus comes here, the PA announces that she can't enter unless permitted. This zone had all of the Metroids located in it until the Restricted Laboratory was ejected out of the station. The only parts left of this zone after the destruction of the lab were a few rooms after coming from Sector 6 and Sector 1. There is a way to get a Power Bomb Tank by Shinesparking into the Speed Booster Blocks in the dead end room towards the Sector 6 entrance.