How to Complete The Doomsday Scenario

Drive to Grapeseed and choose between the Barrage (for a 100k bonus) or the Khanjali (for a 50k bonus).

Drive to the tunnel entrance marked on your map and race to the end, dodging enemies.

At the end of the tunnel, take cover (press the cover button to crouch behind walls or objects) and use the Combat MG to aim for the head of the three Juggernauts.

Head deeper into the tunnel and destroy five crates containing supplies. Split up to do this faster.

Enter the large open room and take the right path towards the Control Tower.

Take cover and defeat the three Juggernauts waiting for you.

Proceed through the door into the Control Center and clear enemies on the first floor.

Go to the second floor and hack the four servers located in each corner.

To hack a server, interact with it while a teammate clears enemies. Aim the beam at the blue circles (Packets) and avoid the red squares (Firewalls). Rotate nodes to direct the beam to mirrors and other nodes to reach all packets.

After hacking all servers, clear remaining enemies and go to the top floor to interact with the Orbital Cannon.

Position the cannon over the trucks holding the drives and shoot them by holding [R2/RT].

Head to the silo marked on your map, proceeding slowly as enemies will be waiting.

After reaching the silo and watching a cutscene (a non-interactive cinematic the game plays automatically), follow Avon with the jetpack.

Shoot down the helicopters attacking you, then take down Avon.

Travel to the Observatory to complete the heist.