Metroid Fusion (GBA) - Part 24: Blackened
Samus doesn't have a lot more to do here in underwater Sector 4 before she heads back above water so she can get Diffusion, which is the highest upgrade available for her Missiles. With this, not only can she freeze one enemy, but all enemies in a single room if you hold the R button to charge it up. She heads back to the Navigation Room, where the computer chastises her for opening the Level 4 hatches without permission. It then tells her that the B.O.X. Security Robot she faced earlier in Sector 3 is now infected with the X parasite and is now in Sector 6, the night habitat. Seriously though, why couldn't the game have just let it blow up the first time so we wouldn't have to deal with it again?! Anyways, I'll talk more about it in the video when Samus actually faces it.