The Airlock

Start by picking up the fresh Gas Mask and looting the dead guard for ammo and a Kalash near the tunnel entrance. Move right around ice blocks to find another Gas Mask in a shed.

Continue to a ladder and climb up. There's an enemy on the middle catwalk.

From the top of the ladder, stay left. Use wooden boards to reach a pipe and cross it to the bottom of the stairs.

Sneak up the stairs, then left towards a shed. Switch to Throwing Knives and quickly kill the two enemies inside. Loot the ball bearing ammo, filter, and gas mask.

If you have a Helsing, you can attempt a silent kill from the shed. Otherwise, exit the shed and sneak right to the ladder. Wait for the guard to stop at the right before climbing. Stay behind boxes, then sneak towards the guard. Go down the ramp, hide by a tall box and railing, and kill the guard with throwing knives when he approaches. Loot the gas mask and a Revolver with stock, optics, and silencer from the crate near the alarm bell.

Cross the middle walkway to the upper level. You can go left down a ramp to loot revolver ammo from a body.

Sneak right and go up the stairs. Equip Throwing Knives or Helsing. Go left and sneak to the doorway of a building. Kill the two enemies inside quickly with throwing knives or Helsing before they raise an alarm. Loot their bodies and find a +10 filter inside. Be aware of a grenade trap hidden in a white plant between the building and the wall outside.

Proceed to the next section, 'Entering the Outpost'.