Marathon's Dire Marsh (Night) map features a secret boss encounter in Upper Complex, which you can only access with the Observation Labs priority item. While this can be done in Standard and Sponsored Survival, it's not going to be easy, especially without a guide.
Below, you can discover how to get into Upper Complex, and how you can spawn the boss via the Observation Labs keycard. Everything you need to know about Upper Complex and its loot (and dangers) can be found right here, so read on!
Marathon: How to Play PvE
Looking to avoid the sweats and stresses of PvP in Marathon? Here's how you can play the Marathon PvE mode from Season 2 onwards.
The steps below are only for Dire Marsh (Night), and they can be completed in both Standard or Sponsored Survival.
How to Get the Observation Labs Keycard in Marathon
The Observation Labs keycard is a random drop from Caches, which are activated via Network Towers.
Before attempting to get into Upper Complex, you're going to need the Observation Labs keycard. This is going to require you (and your team) to activate Network Towers around the POIs with x3 UESC CERTs, which will allow you to get Supply, Weapons, and Gear Caches.
Each Cache will have 3 chests that can be looted, and you might find the Observation Labs keycard in one of them. It's completely random and not tied to any specific Cache, so just try the ones that are closest to you. You can also get the Observation Labs keycard from Wardens that spawn randomly, but this is far riskier and more time-consuming.
I like to do this meta on Triage for the healing bots, but you can take any Shell you are comfortable with. You're also going to want Weapon Caches for the ammo!
How to Open Upper Complex in Marathon
Now that you have the Observation Labs keycard, you can open Upper Complex with either x12 UESC CERTs or x7 UESC CERTs, depending on your preference:
- Method #1 (x7 CERTs) - Head to the north area of Complex, and you can use x7 UESC CERTs to activate a garage door with an elevator. This will be the cheapest way to Upper Complex, but it spawns plenty of enemies you need to kill to unlock the door's security barrier.
- Method #2 (x12 SERTS) - In each corner of Complex, you can find small rooms with stairs. At the top of the stairs, you can spend x3 UESC CERTs, and after spending a total of x12, the doors upstairs will open, which allows you to sneak into Upper Complex without fighting enemies.
Once you're in Upper Complex, you can find an upstairs terminal that can be activated. This will then turn on green buttons around the room, which you need to shoot. The first room will have 3 green buttons, and destroying them will open the next door under the room where you activated the terminal.
If you have the time before exfil, you can also search the entirety of Upper Complex for 7 red buttons to open an additional loot room after the boss, but it takes too much time to do.
You'll then have to proceed into the next room, which has another terminal to activate and a total of 4 green buttons that need to be shot. After, proceed to the next room, which has yet another terminal, and then 5 green buttons. After the third room, you'll be in the boss room.
In the back of the boss room, you can find a terminal where you can use the Observation Labs key. This will spawn a wave of enemies, and to progress the wave, you need to shoot the green buttons. You will need to repeat this for three waves to spawn a gold shield Warden, and when killed, a loot room will open, which has Purple and Gold loot.
You can use a weapon with the Darksight Optics to see hidden numbers. by the green buttons. If you want even more loot, you'll need to shoot the buttons in their ascending order (e.g, if your buttons are 1-5-2-4, then your order is 1-2-4-5). This is not needed and just grants extra loot.
This isn't an easy encounter to do, so if you need additional Marathon guides to help you through it, then we've got you covered:
- How to Use the Cradle
- Best Weapon Tier List
- Best Runners Tier List
- How to Level All Factions
- How Many Players Per Match?
- PvP Tips & Tricks
- How to Get Lockbox Keys
- All Weapon Types & Stats
Marathon
OpenCritic Reviews
- Genre(s)
- Extraction Shooter, FPS, Multiplayer
- Platform(s)
- PC, PlayStation 5, Xbox Series X, Xbox Series S
