How to get inside DMZ Building 21 and find weapon cases

(Image credit: Activision)

The DMZ Building 21 area is a fleeting challenge currently on a timer that limits access. If you have a key card then you'll get the option to drop when it's live, and try to extract a weapons case for series of progressive rewards.

It's a tough challenge though, on top of the timed access that limits your window. So coming up we're going to run through how to get the Defense Research Center, or DRC Building 21 key cards you need to get in, how access works, what you actually have to do and, finally, what Building 21 rewards you earn for all that effort.

What is Building 21 in Call of Duty?

Building 21 is a separate DMZ area in a biological laboratory that acts as a separate, extra hard challange. You can only access it when the area is active with a key card extracted from Al Mazrah. The main goal is to find and extract weapons cases for rewards, with the top prize being the Silver Tox Warzone 2 Chimera blueprint.

How to enter Building 21 in the DMZ

You can enter Building 21 on two conditions. Firstly the area has to be live, which means waiting for the timer to count down. And, secondly, you need to have found and extracted from the Al Mazrah DMZ map with a Building 21 key card.

Building 21 key cards are found in a similar way to way to Warzone 2 DMZ Stronghold keys, appearing as random floor loot. However, while you can't extract with a Stronghold key, you can extract with a Building 21 key. So if you want to run the new area when it's live, extract the moment you find a card and bank it. Only one person in a team needs needs one at least so if you're not having any luck getting one, make friends with someone who has.

How to complete Building 21

Building 21 Velikan — (Image credit: Activision)

With tough enemy AI and other players to deal with a full walkthrough isn't really going to work here, but a basic plan of what you should be trying to do will steer you in the right direction as you fight to survive.

As well as as AI enemies, other players and a Wheelson drone patrolling the building there's also Velikan, a randomly encountered boss to deal with (he's appeared as an operator bundle, in the image above, if the name sounds familiar). You'll get a message that he's nearby if he's close, although you might want to steer clear as he will continually attack you with an incendiary firing grenade launcher if you engage.

There are three floors in Building 21 and most of your focus will be on the lowest and highest levels. Here's what to do and where to go:

When you start, find the Server Room on the west side of Level 1. You'll need to wait for the message that security systems are deactivated before you can access it.
Find the server you can hack and leave one player holding the interact prompt down while the other players hold off an AI assault. When it's done you'll get a message that the Armory is now accessible.
Head to the top floor and look for the Amory in the northeast corner of Level 3 (it's an orange door).
You'll find a lot of loot but your focus should be the safe - open it to get the Weapon Case inside, but beware: the process will warn other players and AI.
Once you have the Weapon Case find an elevator to exfil. It's on a timer so you might have to wait if you were fast.

Building 21 rewards

While the big Building 21 reward is the Silver Tox Chimera blueprint, you'll have to earn it by extracting 6 weapon cases in total. The run up to that includes the following rearwards in this order:

Going Bark weapon charm
Weapon Rover calling card
Roar weapon sticker
Company Sniper emblem
Camo Cloud vehicle skin
Silver Tox Chimera blueprint