Survive Sevastopol with Prima’s Alien: Isolation Walkthrough.
After stepping off the lift, go through a couple of doors until you receive your first objective asking you to Investigate the Central Reactor. Turn to your left and choose the option to Power Up Tram Systems on the device with the cables running out of it, then go to the right and choose the option to Activate Tram.
Start following the signs that lead to the Workshop, then duck inside a room on your right when you encounter a security camera. Take out the hostile Synthetic in the area, then hit up the Access Rewire and turn the Camera Feed off. Proceed to loot all the rooms in the area, making sure not to miss the Ion Flame upgrade for your Cutting Torch.
When you're satisfied that you've stolen everything that isn't nailed down, sneak past the two security scanners up ahead and look for a hatch that gives you the option to Use Ion Torch. Do so, then hop into the vent and follow it until you emerge with the option to save your game. Backup your progress and then move through the door into the next room.
You should see a Synthetic standing on a platform. Beat him to death with your Maintenance Jack, then hop on the platform and choose the option to Power Up Workshop Controls. Follow the wires that leave that device to another and choose the Power Up Workshop Controls for a second time. This will leave one more device, and when you approach it the option will be exactly the same. You should now be able to approach the nearby 2000-KJVS Generator and opt to Activate Switch, lifting a vehicle in the middle of the room to reveal floor access to the ventilation system.
Hop into the vent and follow it until you have the option to Climb a ladder. Do so, and when you emerge you will have a corridor in front of you and another one to your right. Take the one on the right, following it until you reach a room with a Facility Management sign hanging from the ceiling. This will cause your objective to update to Unlock the Shutter.
Follow the arrow on the Facility Management sign until it takes you into a room with a table and chairs. You'll need to deal with the Synthetic in the area, but you might want to let him come at you, passing by him on the opposite side of the desk that he chooses to attack you from. Move into the next room and collect the Boltgun from the desk, then shoot the Android for being a jerk-face.
With that problem out of the way, access the Sevastolink terminal next to where you picked up the Boltgun, browsing to the Personal folder and taking note that the code to unlock the shutters is 6832. Move your cursor to the Utility folder and input the code.
Now that the shutters are open you will have an updated objective asking you to Get to the Reactor. Backtrack all the way out to where you saw the Facility Management sign, then go through the door with the Reactor Access sign above it. In fact, keep following the Reactor Access signs until you reach a door that gives you the option to Call Elevator. When it arrives, step onboard and hit the button that is labeled To Central Reactor.
Exit the elevator and go through the door with the Central Reactor sign above it, following the corridor until you re-claim your Shotgun and Revolver at the bottom of a ladder. Climb the ladder, saving your game at the top before getting back to following the Central Reactor signs.
When you come to a room that triggers a conversation between Amanda and Ricardo, step onto the lift and choose the option to Use. This will update your objective to Descend to Base of Reactor. When the lift ride ends, whip out your Boltgun and start scoring headshots on the no less than four Synthetics that will begin to walk you down. When they are no more, work your way around the central catwalk in a clockwise manner, turning left and following the signs to Beta Core - Primer and Beta Core - Release. Continue to follow the catwalk in a clockwise direction until you can pass through a door called Reactor Maintenance. This will lead you to an elevator where you can push the button labeled To Central Reactor Maintenance.
That elevator ride will deliver you to a place that can only be described as the worst place that you can imagine in video game history, and rather than run away like you should, your objective will be to Destroy the Nest. Awesome.
Move into the nest to find the option to save your game, and at about the same time you'll get an objective to Overload Alpha Core. Go through the nearby door, following the creepy tunnel until you get attacked by a Facehugger. Shoot it with your Shotgun and move into the central area, picking up the Flame Thrower from the desk in the corner. This is also where you'll want to Enable Conduit Interface before moving to the center of the room and choosing to Disengage Locking Mechanism. Next up, move to the other side of the device and choose to Activate Alpha Conduit.
It's time to backtrack through the creepy tunnel, and as you do you should see an updated objective which asks you to Overload Beta Core. When you get to the save game mechanism, be on guard and have your Flamethrower ready to fend off the Alien, then head down the opposite tunnel that has the busted Secondary Coolant Storage sign above it.
Follow the tunnel until you see a vent on the right side, sneaking through it and hanging a right when you exit. Keep working your way forward until you reach another save game mechanism. You're going to want to do that after making sure the coast is clear, and shortly after you'll get an updated objective advising you to Redirect Power to the Central Core.
Once your game is saved, you’ll want to follow the wall as it makes a sharp turn and puts you into a tunnel that runs parallel to the one you were just in. Follow this new tunnel until you see a vent on the left, then crawl through until you reach a room where you can Restore Power. This will once again update your objective to Overload Beta Core.
Jump back into the tunnel and retrace your steps to where you last saved your game, going up the steps and into an office where you'll be able to Enable Conduit Interface. The game will again remind you to Overload Beta Core, so exit the office and approach the console in the middle of the room. Choose the option to Disengage Locking Mechanism, then Activate Beta Conduit on the opposite side.
Your new objective will be to Return to the Central Reactor, so make your back out to the area where you first discovered the nest, hopping on the elevator and choosing the option to go To Central Reactor Maintenance.
When you step off the elevator, your objective will be to Overload Alpha Core. Move forward on the catwalk and turn to your left, following the sign that says Alpha Core - Primer. This will take you on a clockwise tour around the area, and you'll have to take out at least four Synthetics along the way. When you reach a console that gives you the option to Overload Alpha Core, do it.
Keep popping into your Motion Tracker to find where your objective is located, then follow it to a console that will give you the option to Deactivate Core Limiter Alpha. You'll find this near the center catwalk where the four Walking Joes just came from. Keep moving around the central catwalk in a clockwise direction until you find a console that gives you the ability to Deactivate Protective Relay Alpha. This will give you the objective to Overload Beta Core.
Use your Motion Tracker to locate the next device, then approach it and choose the option to Overload Beta Core. Head back to the central catwalk and Deactivate Protective Relay Beta. Then use your Motion Tracker to hunt down and Deactivate Core Limiter Beta.
With all that computer mumbo jumbo out of the way, your new objective will be to Redirect Power to the Central Core. Spin around from where you are to see at least four Androids headed your way. Ignore them, running around the catwalk and all the way back to the area where you exited the nest, then use the console and choose the option to Divert Power to the Central Core. You'll then get another objective, this time telling you to Initiate Purge from Reactor Control.
Once again, run all the way to the opposite side of the room and head through the Emergency Exit, then dive into a ventilation system on the left and Climb up the ladder at the far end. Keep following the ventilation until you drop into a control room, then approach the console and Initialize Emergency Purge Sequence. Do the same thing on the other side, then move to the middle of the console and Commence Purge Sequence.
After basically reprogramming the entire station your new objective will be to Return to Ricardo. Head through the door labeled as Transit Station, then keep following more Transit Station signs until you actually reach the right area and get an updated objective asking you to Go to the San Cristobal Medical Facility. Press the button to Call Transit at Towerlink 02, and when it arrives choose the option to go To SCIMED Tower. This will update your objective again, this time to Get to Sevastopol SCI/MED Tower. It will also bring the mission to a close.
Continue to Alien: Isolation - Mission 15: The Message.