Metroid Prime 3: Corruption Part 48: The Fourth Part of the Valhalla
The road forks here. Take the right fork, and you will get to a another door. Enter in.
There are lots of things to analyze. Do all the data stuff, and get the information. On one side of the room there is a section that can be destroyed with an explosion. Hit that area three times with missiles. Some Hopping Phazons will come up and try and kill you, but repeated hits will take them out. There is a section revealed that needs a grapple grab. Take the ball tube that will be revealed, and you can get a missile expansion.
Go back to the Security Access, and some Hopping Metroid that weren’t there before will try and stop you. Take the door at the end of the hall. (Not the one you originally entered from).
You will enter a room where a metal panel blocks something important. Use the grapple-grab to get rid of the panel, and then put an energy pod there. An elevator will be revealed. Taking the elevator up and out the door will reveal a room. There is a morph ball area that if you go down a tube, you will find another missile expansion.
Port Observation Deck
In this area, you will be blocked by debris. If you morph ball, you can get past the debris, but then a door will open that is full of suction.
When the door shuts behind you, the suction will stop, but you will be attacked by Phazon Metroids. Take them all out. Keep walking down the hall and you will see a room with a lock that has to be taken out at four places simultaneously. Take all points out at once with four seeker missiles.
Entering this room will reveal not much but a view of a generator, however, there is a weakspot. If you analyze it, you will find a door vulnerable to explosive blasts. Take it out using a missile. From here, you will face off with bad guys, and then grapple grab some panels off some turbines. Then insert energy packs into them. A ball tube will open underneath. So what you need to do is follow it until you get a ship missile upgrade. Eventually, you will be back into the Security Access, and you’ll need to retrace your steps to the Port Observation Deck.
This time, instead of following the hall, go immediately to your right after dealing with the Phazon Metroids. You will need to insert your Energy Pack here, then the door will be available to open.