This a story related achievement and cannot be missed!
This achievement will be obtained by playing trough the level CURSED
in chapter three. You will need to blow up two tunnels, one with a bomb which you also need to find.
At the start of the level follow your partner Khan to the survivors. They will provide info about the current situation. Basically what you need to do:
- Detonate a pillar about halfway in the station.
- Find the bomb where the demo squad got ambushed.
- Use the bomb to blow up the tunnel.
This level has infinite enemies so I advise you to just sprint to all the objectives. Dodge and ignore the enemy Nosalises coming at you.
If you start from where the survivors are, run down the main corridor until you find a staircase on your right hand side. Run up the stairs and walk up to a wooden pillar in the room that you enter. Press the action button/key, this will ignite a grenade. Now double time back from where you came from because the room will blow up and collapse and this will kill you. Make sure to also pick up the diary in the same room BEFORE igniting the grenade because after the room has collapsed you will be unable to collect the mentioned diary.
Now from the first objective run back down the stairs and head left and then immediately head left again. You will now enter the area with the train tracks (right tracks as seen from the survivors point of view). Now run all the way to the back of the tracks, away from the survivors, and you will notice a big fuel tank makeshift bomb. Pick it up with the action button/key.
Now run to the tracks on the other side of the platform, so left and away from the survivors. All the way at the back of the tunnel you can again press action to ignite the bomb. Now again, make a run for it. The bomb will blow up and you will unlock the achievement.
One additional tip I can give you is to press
on controller or hold the M key on PC to open your Diary. There will always be a green arrow pointing to your objective so you can just follow that if you get lost.
Here is a video to clear up any confusion: