Where to use the blackmarket weapons locker key in DMZ in Modern Warfare 4

The Call of Duty: Modern Warfare 4 DMZ blackmarket weapons locker key is one of many keys in the extraction mode, and it's used to open, as you may have guessed from its name, a locker that can contain rare weapons and loot. Much like the gun store weapons locker key, however, the blackmarket weapons locker key can be used in two different locations.