Updated on July 28, 12:47 p.m. (GMT+8): Improved relevancy.

Warzone 2.0’s exfiltration-style DMZ mode is alternately fun and incredibly frustrating.

The high-stakes gameplay makes it extremely satisfying when you manage to extract successfully, but having another squad kill you just as you board the helicopter is quite another thing entirely.

Building 21 is a top-secret biological laboratory that holds the Chimera assault rifle and other high-tier loot, but it requires an access card to get in.

Here’s where you can find the Building 21 key in DMZ.

Where to find Building 21 key in DMZ

Call of Duty Warzone 2.0 DMZ Building 21
Credit: Activision Blizzard

The Building 21 key has a chance to drop from several sources in DMZ:

  • SAM site drops
  • Airplane supply drops
  • Commander Helo supply drop

SAM sites are marked by a white missile icon on the map. To obtain the drop, you will have to clear out the enemy AI, then activate a console to begin a countdown timer. This will call in enemy reinforcements, and you will have to defend the area against them.

Once the site has been secured, the missile battery will shoot down airplanes that pass over it. The plane will release a supply drop for you to loot.

Warzone 2 DMZ building 21 key supply drops
Credit: Pro Game Guides

The second method is to wait for airplane supply drops, which kick off when the timer hits 10 minutes. An airplane will fly over the map and drop three supply drops in its path. These are marked by an orange dollar icon on your Tac-Map.

The third and most challenging way is to take down the Commander Helo. The SAM site can help you with this, but you can also shoot it down yourself. The Helo is marked by a white skull icon on the map.

Of course, if you’re feeling lucky, you can attempt to grab it off other players. Extracting with the key will grant you access to Building 21.

The building is available as a separate level from Al Mazrah, and you can choose which location you want to drop into.

Find out where to find all the hidden caches in Al Mazrah and the fastest vehicles to get around. Follow ONE Esports on TikTok for more Call of Duty highlights.

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