|This article is written from the Real Life point of view|
Facing a Huge Reaction (巨大生命反応へ向かえ), as named on the Metroid Prime & Fusion Original Soundtracks, is an uplifting theme in Metroid Fusion. It is first heard after Samus is directed toward the Arachnus-X, and continues during a cutscene where Samus reflects on Adam Malkovich, who her computerized CO reminds her of. The theme stops when Samus ascends to the Operations Deck, but resumes when she enters the hidden tunnel there after she acquires the Missile data. It is one of the more recognizable themes from Fusion.
It is heard again when Samus links up with the computer (which she privately names after Adam) after defeating Serris, and is directed to Sector 3 to acquire Super Missile data. The theme continues until she reaches the Security Room and unlocks Green Hatches. It is then heard when Samus is briefed in Sector 6, until she leaves the Recharge Station, and resumes when she returns to the Navigation Room, continuing until Samus enters the first frozen room in Sector 5. Later in the game, the theme plays as she moves toward the Habitation Deck, and encounters the Dachoras and Etecoons, then continues as she returns to Sector 5 to use the Data Room there. It plays again after the defeat of Nightmare, and continues until Samus reaches the underwater portion of Sector 4. This is the last time it is heard in the game.
The theme can be heard here.