Survive Sevastopol with Prima’s Alien: Isolation Walkthrough.
Mission starting points are a little blurry in Alien: Isolation, so your objective should be to Take the Elevator to the Lower Hospital, but will soon update to Find a Trauma Kit. Step off the elevator and save your game if you so desire, but given how close to the beginning of the mission it is you may want to skip this.
Take a left before reaching Cold Chamber 1 and look for a door that has a Stun Baton jammed into it. Grab this item to add it to your inventory, simultaneously opening up the door it was holding shut. Head inside and use the Sevastolink terminal, choosing the Utility folder and selecting the option to Activate Cooling System. This should allow you to approach three of the four Hydrogen Cylinders in the room, choosing to Engage Coolant on all but the U6 unit which is located next to the cabinet we spent a few hours cowering inside.
Exit the room you're in, turning right and going into Cold Chamber 2. Be careful that the Alien doesn't spot you through the glass that separates this room from the one you were just in. If you see him wandering around, hide behind one of the tables. With the coast clear, grab the Hydrogen Cylinder from the floor and make your way back to the original room, the one with the Sevastolink terminal. Approach the final cylinder and choose the option to Insert and Engage Coolant.
Leave this room one more time, taking a left and heading into Cold Chamber 1. Hide behind the table until you see the Alien complete its rounds through the glass, then use the Access Rewire on the wall. Turn off Air Purification and switch Vent Access on. This will update your objective to Investigate Lingard's Office for Information. Exit Cold Chamber 1, walking straight forward and saving your game before continuing.
Head back toward Cold Chamber 2, but rather than go in that room, look to your left and climb inside the vent that's on the wall. You can only go one way, so climb the ladder and drop through the floor when you run out of vent to traverse through.
Loot this room, hiding from the Alien in one of the lockers if it makes an appearance. When you're ready, leave the room and take a left, following the corridor and ducking into the first room on your right. Once safely inside, access the Sevastolink terminal and browse to the Utility folder, selecting the file Report: Lingard to trigger a cut scene.
When the cut scene ends the objective will update to Search Operating Theater for Trauma Kit. Exit the room to see a sign on the wall that says Staff Gallery, turning left and following the hallway until you pass a dead body, then actually entering the Staff Gallery itself. Continue moving along, passing through the door that says Hygiene Area and traveling down the corridor. Turn right into the Staff Quarters and take an immediate left to head toward Facility Administration, going inside the room with the same name when it appears on the left hand side. As you try to use the door on the opposite side of the room your objective will update to Find Keycard to Access San Cristobal Medial Wards. All these wonderful hacking tools and we need another keycard.
Exit the room through the door you entered, turning left and going into the Security Desk area. In here you'll find the option to save your game, after which you'll need to access the Sevastolink terminal, browsing the Personal folder and selecting Morley: Update and Codes. It's here you'll find an extremely important code to accessing San Cristobal's central wards is 2505.
Exit the terminal, turn around and choose to Enter Passcode next to the save game mechanic. Grab the Keycard, leave the room and take a right before ducking back into Facility Administration. Use your newly found keycard to open the locked door, passing into an area with a very dead person sitting in a wheelchair.
As soon as the door opens, turn to your left and then take the corridor on your right. Go to the far end and use the door, passing through and into the Operating Theater. Approach the dead body on the table and choose the option to Use, updating your objective to Access San Cristobal Medical Reception.
Head through the door with the Ambulance Bay sign above it and take a right, then another right when you reach the main area. Look for a vent in the floor and open it, jumping inside and following the only available path to very end. Climb back out of the vent where you'll receive an updated objective to Initiate San Cristobal Medical Evacuation Procedures.
Approach and fire up the nearby 2000-KJVS Generator, then move to the opposite side of the room and do the same over there. You might also consider saving your game at this point, but that's optional.
With both generators on, it's time to approach the center of the room and choose the option to Use Security Access Tuner, completing the mini-game and updating your objective to Escape Through San Cristobal Medical Reception. Just be careful of the Walking Joe in the area, they can be wildly unpredictable.
Head through the now open door, using your Stun Baton on the Synthetic if it gets in the way. You'll also want to be very careful of vents in the roof, should there be a goopy liquid coming out of it, the Alien is there and will mess you up if you pass underneath.
Move down the corridor with the High Dependency Unit sign above it, turning left and going into the door labeled Operating Theater. You may recognize this room from before. Pass through it and out the door on the opposite side, taking a right and moving to the far end of the hall. Once there, turn left and pass underneath the Medical Reception sign, following corridor as it curves to the left.
Continue along this dark hallway, hiding under beds if you come across anything that moves, including the Alien. When you come to a Medical Reception door on your right, take it and follow the Exit signs until you pass through a door at the end of the hallway. This will trigger a cut scene, and when it's over your objective will be to Escape.
Get to your feet and climb the ladder directly in front of you, then jump and climb another. Hop into the ventilation shaft and follow it as far as you can. When you drop to the floor, get on the elevator to receive and updated objective, Get to Seegson Synthetics. This will also bring the mission to a close and move you on to the next.
Continue to Alien: Isolation - Mission 7: Seegson Synthetics.