Sector Zero



Sector Zero was a mostly unexplorable area of the Bottle Ship, designed after Tourian. The entrance can still be reached through an elevator in the Cryosphere. This sector contained Metroids, most of which were genetically altered to be unfreezable, as well as MB's original body. MB's new body informed Samus of it while she was posing as Madeline Bergman, though she did not mention the unfreezable aspect of the Metroids.

When she arrives, she encounters an Infant Metroid at the entrance that reminds her of the Baby. After Samus takes some time to think about whether or not she should kill the infant (having a flashback of the Baby's hatching in Metroid II: Return of Samus), she ultimately decides to destroy it. Just as she is about to, however, Adam shoots Samus in the back to keep her from doing so. She falls to the ground with her Power Suit disappearing. Adam then steps in and kills the infant just as it decides to attack her.

Adam shooting Samus was to not only keep her from killing the infant, but to keep her energy low so she that she could not strongarm her way through Adam and into Sector Zero. Adam mentions that the Metroids are altered, and thus, cannot be destroyed by their weaponry. Adam decides to sacrifice himself by creating enough damage throughout Sector Zero to detach and self-destruct as programmed, destroying the Metroids, Sector Zero, and Adam, leaving a heartbroken Samus.

She must then escape Sector Zero before the rest of the entrance falls off, sucking Samus into the vacuum of space. She enables her Gravity Feature in order to do so, and must race against time to flee from the breaking portions. Super Zebesians are present in the area as she escapes.

When Samus returns, a large indestructible hatch blocks the way prior to the detached Sector. Different music also plays during these visits, which seems to be sad and in reference to Adam's death.

Trivia

 * Sector Zero is also the name of the area explored on Norion.
 * Sector Zero was a Tourian replica created by the Galactic Federation. The organization was known to have blueprints for a Tourian-like base at some point in the past. These blueprints are shown in the third of Metroid Prime 3: Corruption 's preview trailers.
 * It should be noted that MB did not tell Samus about the "Unfreezable" characteristic of the Metroids of Sector Zero. This is undoubtedly because Samus posed a threat to MB and her goals. As planned, Samus would have rushed into Sector Zero defenseless and be annihilated by the indestructible Metroids, were it not for Adam's intervention (who was convinced the Madeline Bergman Samus had met was not to be trusted). In addition, Super Zebesians fill the entrance tunnel leading to Sector Zero as Samus escapes the area, implying MB had sent them.
 * Since this area is designed to be a copy of Tourian, it is quite possible that the sector featured Rinkas, Cannons and Zebetites.
 * A similar area later plays the same role during Metroid Fusion on the Biologic Space Laboratories research station in an area called the Restricted Laboratory. There are many similarities between the two: Metroids were being raised, station had a fail-safe protocol causing it to detach if it substains too much damage, both stations were detach by someone other than Samus, and both stations were successfully destroyed.
 * While Samus would normally be wearing it on her leg, the black holster holding her Paralyzer is absent during the entire Sector Zero scene. It is possible that the developers overlooked this detail. This is supported by the fact that she has the Paralyzer holster if she dies after the Sector Zero cutscene.
 * It appears that at least one unfreezable Metroid escaped from Sector Zero and made it into the Cryosphere, as evidenced by a dead Gigafraug in that area that exhibited signs of Metroid predation. Also, during the cutscene in which Adam explains to Samus the existence of the modified creatures, the dead Gigafraug is shown right before an unfreezable Metroid (presumably in Sector Zero) is depicted breaking its container.