Reactivating the Vault on Elaaden will restore the planet’s atmosphere to a habitable temperature. There are also a series of bonuses and puzzles located within.
After activating all three monoliths around the desert surface of the planet, venture into the Vault entrance that appears and take the gravity well down and activate the terminal SAM indicates.
EditVault Entry Puzzle
In order to open the door from the antechamber into the main portion of the Vault, Ryder must solve an infuriating lever puzzle.
The good news is that the solution is fairly simple once you fully understand which terminals each interface controls. If the terminals that appear were numbered, from left to right: 1 – 2 – 3 – 4 – 5, you would want to first activate Terminal 5 then Terminal 4. The door will spring open and Ryder can be on their merry way.
Fight your way through the first room and down through the hallway into the massive open chamber leading to the heart of the Vault.
In order to reach the central control terminal, you’ll need to extend the bridge to it and unlock the door blocking your path.
EditExtend the Bridge
When facing the purification chamber on the central platform in the main chamber, jump to the platform on your left with the large plant growing on it.
On the right side of the next platform is a control console that will extend the bridge leading into the control room.
This area can also lead to a bonus area – before returning to the central platform, fight (or sneak) your way up the zig-zagging pathways to the far side of the chamber after activating the bridge (it’s to the east on your compass).
Take out the force of Remnant machines that guard the door, then open the door and climb up to the bonus terminal to solve the glyph puzzle and earn 2 skill points.
This chamber also unlocks the escape-route access to a chest full of valuable Remnant items.
To unlock the door that will lead back to the Vault entrance after the purification sequence has begun, you’ll need to solve a short puzzle. There are five terminals surrounding the pillar with the Skill terminal on it, and they need to be activated in a specific order.
First, activate the terminal on the eastern wall of the room, directly opposite the door we’re trying to open. This terminal, unlike the rest, does not have a Remnant light next to it – once you activate the terminal, you’ll notice the light at the terminal to your left will sink into the ground.
Activate this second terminal and follow this pattern – activating terminals without the light – until a sixth terminal raises from the floor directly across from the locked door. Activate this terminal to unlock the door, then return to the central platform in the main chamber.
EditUnlock the Door
To unlock the door to the Vault’s control room, locate the two terminals facing the door across the chasm on the west side of the main chamber – activate them both.
The path that appears will allow you to reach the terminals on the two pillars across from you – jump-jet across the gap and activate both terminals, then return to the central platform and initialize the first two terminals once more.
This will raise a central platform with a terminal on it – make your way over and activate it to open the door across from you.
Fight through the hallway until you reach the terminal at the far end (overlooking the bridge). Activate it to unlock the door into the purification chamber, then return to the central platform.
Cross the bridge to enter the Vault control room and eliminate the Remnant bots inside, then activate the purification system.
If you unlocked the Remnant tech chest in the room with the bonus terminal, cross the bridge out of the control room and jump-jet and dash your way to the platform with the tree on the east side of the central platform.
Sprint back up the zig-zagging ramps and up to the door, then head through and grab the chest.
Interface with the terminal to complete the purification sequence and reset the vault.
Source: IGN Video Games