Sector 5 (ARC)
Sector 5 (ARC) is one of the six sectors onboard the B.S.L Research Station. It maintains an arctic climate and and is used for research on many creatures that reside in that environment. Some X Parasites make their way into this sector and are mutated by the cold, enabling them to freeze Samus on contact if she is without the Varia Suit. Sector 5 is also where Nightmare is kept.
At first, Samus is unable to enter the frigid areas of Sector 5 without taking damage due to the effects of the Metroid vaccine. Once she acquires the Varia Suit in Sector 6, Samus is free to explore most of ARC. During her first visit, Samus acquires the Ice Missiles. On a later visit, she acquires the Power Bombs and has a brief encounter with the SA-X.
- "Sector 5 (ARC) is sub-zero. You're still susceptible to cold from the vaccine side-effects, so you'll take damage if you even set foot inside there. Avoid Sector 5 for now" —Adam Malkovich (Metroid Fusion)
- "The damage seems to have been caused by a creature kept here by the researchers, who named it... the Nightmare." —Adam Malkovich (Metroid Fusion)
- "This sector is used to research creatures living in extremely cold habitats." Metroid Fusion Instruction Booklet, Pg 26