Survive Sevastopol with Prima’s Alien: Isolation Walkthrough.
As you exit the transit and have a chat with Ricardo, your objective will update to Find a Short-Range Ambulance. Head up the stairs to your left and pass under the Towerlink Transit System sign, moving forward and choosing the option to Use Ion Torch. Go through the door and walk forward to the elevator, stepping on and pressing the button to go To Primary Care Floor.
Step off the elevator to get a new primary objective telling you to Find an Ambulance Craft in the San Cristobal Medical Emergency. Head left and through a door labeled Emergency Room, following the hall and turning left at a High Dependency Unit sign. Follow the corridor as it loops to the right, being careful not to let the Synthetic spot you as you pass the dead guy in the wheelchair. Pass underneath the Operating Theater sign and keep following this corridor until it curves to the right again. In fact, stay in this corridor until you reach the reach the Ambulance Bay sign, then pass under it and keep going.
When you enter the Ambulance Bay, grab the Flashbang V.3 off the gurney, then approach Towerlink 01 to receive an updated objective telling you to Find a Level 3 Upgrade for the Access Tuner. Head to the back right corner from where you entered and pick up the Level 3 Security Access Tuner, then take note of your new objective telling you to Hack the Door and Board the Shuttle. Approach Towerlink 01 and complete your objective.
Once you're onboard the shuttle, approach the cockpit and choose the option to Launch Ambulance Shuttle, then sit back and enjoy a short cut scene. When it's over and you've disembarked, approach the save game mechanism and backup your progress.
You should soon have a new objective that is telling you to Explore the Anesidora. Go through the narrow corridor to the left of where you saved your game, passing by a room as you follow the objective on your Motion Tracker. Soon your objective will update to Bring the Anesidora's Systems Back Online.
Continue to walk with your Motion Tracker up as you make your way through the corridors. You'll reach an audio log that you should play, but continue to move forward until you find a room on the left with a door inside of it requiring a passcode. Access the Sevastolink and browse to the Personal folder, then selecting the Technician's Report. This will reveal that the door code is 4510.
Once you're through the door, go through a couple of rooms until you can choose the option to Restart Generator, a task you'll have to repeat on the other side of the room. When that's done, hang tight as the center console activates, then use your Security Access Tuner to hack it.
Once the power is back online, you'll have a moment before your objective updates to Find Marlow. Feel free to wander around, but when you do get the objective, use your Motion Tracker to hunt the jerk down. When you come to a door that requires you to use the Security Access Tuner, do so and go through, checking your Motion Tracker in place of the signs that would normally be around. When you come to another door that requires your Security Access Tuner, use it to gain access. Continue moving until you reach a point where you can save your game. Do so.
Head through into the Power Core where you'll get a new objective that tells you to Use Terminal. Walk up to the console and choose the option to View Flight Recorder Data, then sit back and enjoy an extended cut scene.
When the scene ends, you'll need to wait for your objective to update to Shut Off Fusion Systems to Prevent Overload. Look around the room until you see the option to Charge Auxiliary Generator and select it. Wait for Taylor to do her part, then choose the option to Hack Maintenance Terminal and immediately after to Deactivate Fusion Relay.
With all of that out of the way, stand around and twiddle your thumbs until your objective changes to Escape. To do this, you will need to sprint through the ship, all the way back to the shuttle that you took to get here. You might get interrupted by a scripted event or two, but get back to your feet and keep moving. When you reach your destination, choose the option to Launch Ambulance Shuttle. That will do it for this mission.
Continue to Alien: Isolation - Mission 16: Transmission.