After the introductory scene, move forward through the vent until Artyom drops down to the room below.
As you land, there is a box behind you that you can loot to for a Medkit, ammo and throwing knives in it. When ready, move forward and around the corner opposite. Disable the light here and enter the large room. Look through the window in front and watch the entire scene for a Morality Point .
Turn to the right and work your way along the wall. There is a light on the left hand side of the corridor around half way up the stairs there. Disable this. Continue to the next corner and sit behind the crates here. Look around to the left.
There is a pair of enemies standing around a fire here. Wait for one to head over to the intercom on the wall nearby. Afterwards, follow him down the hallway and back into the room you came from. He will open a locker here. Sneak up to knock him out. Grab the custom pistol. You will earn an achievement/trophy and a Morality Point for your effort.
Note: For finding the secret custom weapon, you will earn the Achievement/Trophy ‘A Present’.
Return back to the end of the hallway to the shadows behind the crate in the corner and observe the other enemy still here. When he is finished with his punching exercises he will patrol back and forward in front of the lamp here. Wait until his back is to you and knock him out. Turn the lamp off. There is a throwing knife in the paper target near the open door to the next area.
Return to the entrance hallway and climb the stairs. At the top, stay in the shadows and wait for the two guards here to patrol to the other end of the room. Once will start working on a wall panel. If you are patient, the other guard will patrol back to his start position. Take him out when it is safe to do so. Work your way over to the far end of the room and take out the guy working on the wall.
Climb down the stairs nearby to end up in another hallway. Stay in the shadows at the base of the stairs and a guard will patrol into the hallway here from the room to the left. Take him out. Look into the main room to the left.
There are two more enemies in the central room here. One will patrol the length of the room, whilst the second will remain working at a desk on the opposite end of the room from the doorway here. Sneak up on the patrolling guard to take him out and then head over and take out the man at the desk. Now that the area is clear, look on a chair next to some bunk beds on the left side of the room and interact with the Accordion [Instrument 1/1] .
Return to the second hallway and continue through the door at the far end. As you enter the next room an enemy will be cowering on the floor in front of you. He poses no threat, but there is a custom weapon – propped up against the rack next to him. Continue to the far end of this area and use the makeshift ramp on the left to climb up and into a hole in the wall. Drop down the other side.
Make your way through the planters here towards the door on the opposite side of the area from the entrance. Stay in the shadows to the left or right of the door and wait for the flickering light to go off. Once the guard patrols across the pathway directly in front of the door away from you go into the door and turn left (don’t turn right! There are 3-4 baddies standing here!). Interact with the switch here to turn off the light. Hide in the corner behind the crates nearby and knock out the guard that comes to investigate the switch.
Continue across the bridge. As you cross, wait for the guard on the far side to start patrolling to the right before crossing to the far end. As you reach the end, quickly turn to your left and hide in the shadows behind the machinery here. When the guard patrols back and into the small alcove opposite the end of the bridge with the lamp in it, follow him in and punch him out. Turn off the light.
Follow the fence back to the right and when you reach the hallway turn right. You will see a guard sitting in a chair with his back to you nearby and at the far end of the area another guard patrolling. Wait for the patroller to go around the corner and knock out the guy in the chair. Turn off the light on the table next to him. Loot the other chair here for +10 Military Grade Rounds .
When the guard at the end patrols back into view, sneak up and take him down. Turn right when you reach the corner and take out the guy on the crate here.
Enter the open door and climb down the stairs. Open the door at the bottom. As you enter, you can check out the side vent to the right and at the end you will find a container with ammo and med kits inside. Backtrack to the door we came in from and take the stairs to the left down to the main floor below.
Look below the stairs we just descended to find a ladder leading down to a lower set of tunnels. Drop down here and follow the set path around the corner. Knock out the patrolling guard here when he turns his back to you. Enter the small alcove along the left wall and climb the ladder here to return to the main floor.
Stay in the shadows here and wait for the guard to patrol past on your right. When he is not looking sneak over and through the open door directly in front of you and slightly to the right. There is a container on the counter here that you can loot for some ammo . Leave the far end of the small room and immediately turn left. Drop down the hole in the ground to reach another set of tunnels. Follow the path to the right for a lockbox containing +10 Military Grade Rounds and take the left path at the next corner. Follow the watery tunnel all the way to the end and climb the ladder back to the main floor.
After emerging, you will be beneath a set of stairs. Turn to the left immediately and stay in the shadows. Work your way over to the other set of stairs nearby taking care to not let the patrolling guard see you. At the top of these stairs, enter the open door and take out the guard working on the wall and disable the light. Loot the safe in the corner for +15 Military Grade Rounds . Return to the main room and return back down the stairs.
Wait for the guard here to patrol through the shadows and sneak up and take him down. When it is safe to do so, climb the set of stairs that you ended up beneath when you used the previous ladder. At the top of the stairs, immediately conceal yourself in shadows and wait for a guard to patrol into the area from the door on the left. Take him down when you get the chance. Enter the door he came from and look on the desk for Diary Note [Note 1/1] .
Return to the platform at the top of the stairs and pull the lever on the wall next to the desk with the blue radio on it. This will open a door below. Drop down to the main level via the space to the left of the lever and enter the now open door.
As you go through the door, you will note a broken railing on the left. Drop down here to the water below. Move forward a few steps and keep your eye out for a trip wire on the ground here. Find the side closest to the gas canister and interact with it to disable it. Climb the ladder and turn left, work your way over to the hole in the wall for a scene.
At this point you will earn an achievement/trophy and a Morality Point if you completed the level without killing anyone.
Note: For completing the mission without being detected, you will earn the Achievement/Trophy ‘Invisible Saviour’.
When you regain control, sneak up and knock out the two guards watching your friend and then when they are down approach your buddy for another scene. Afterwards follow him into the nearby tunnel to complete the mission.