Part 10

Mission 3: Fight: Gore Nest 3
Defeat the Possessed Soldier and Possessed Engineer, then destroy the Gore Nest. Imps and Hell Razers will spawn, followed by a Hell Knight.

Mission 3: Finding the Blue Keycard
Locate the Auto-Map on the catwalk. Exit through the upper door to find the Blue Keycard. Two Hell Knights will spawn; one near the yellow keycard door and another near the field drone. Drop down to the Yellow Keycard area to find SECRET 3.6, COLLECTIBLE 3.2, "Possessed Engineer Model, Vaultguy" near molten metal streams.

Mission 3: Fight: Gore Nest 4
Destroy the Gore Nest. Imps and Possessed Soldiers will spawn on the upper floor, with some Imps appearing downstairs. The fight concludes with a Hell Knight, with gas present, making the chainsaw a good option. A Health Station is available upstairs.

Mission 3: Once all four Gore Nests are destroyed
Navigate to the waypoint, potentially facing Imps. The Turbine Room door will unlock.

Mission 3: Fight: Turbine Room
Survive two waves of Imps and Hell Razers. The first wave ends with one Hell Knight, and the second wave ends with two Hell Knights. Exit through the top of the room on the opposite side of the entrance.

Mission 3: End of Mission
Proceed down a hall with ELITE GUARD 3.3. Open the Shutters to trigger a cut-scene with Olivia Pierce. Immediately after, an Imp and two The Possesseds will spawn.

Mission 4: Argent Facility "Beginning of the End"
This area is revisited in Mission 6. Combat Challenges include "Walk the Path," "Bird's Eye View," and "To Be Knighted." The "To Be Knighted" challenge may require the Jump Boots or specific positioning to perform glory kills from above.

Mission 4: Introduction
Open the Airlock into an industrial area. Jump to the lower platform of an octagonal structure, then follow green marker lights on the cliffs to the upper platform. Cross the broken bridge to reach RUNE CHALLENGE 4.1: "Vacuum." After completing the challenge, equip the Vacuum Rune from your Dossier. Optionally grab ammo on the right path; continue left. Near a closed door, find Health, Ammo, and CODEX ENTRY "Environments / Argent Facility." Behind barrels to the left, find a Classic Doom Level Lever. Pulling it reveals the "retro" level.

Mission 4: Fight: Gore Hallway
Enter an automated door into a hallway. Midway down, find SECRET 4.5, CLASSIC MAP 4.1 "Doom - Toxin Refinery" if the lever was pulled. Continue to face two Possessed Securities and The Possesseds. Imps will spawn, followed by more Imps and a Hell Knight. Retreating into the hall is an option, but monsters may spawn behind you.

Mission 4: Fight: Force-Field Gore Nest #1
Jump over a blockade to reach a large blue force-field. Kill the Imps, Possessed Engineers, and The Possesseds below. Destroy the Gore Nest. You will then face two Hell Knights, two Hell Razers, and several Imps.