DMZ field manual
MW4 DMZ Keys: Read Grids & Identify Locked Rooms
Use a key’s description, map grid and entrance type to find the intended room without inventing fixed spawns.
Read the item description
Read the exact key name and location text before traveling. The official Hajin guide says keys include a map grid. Letters move west to east and numbers north to south; its D7 example points to Imjin Farmland. This is a grid-reading example, not the name of a guaranteed key drop.
Check the door and alternate entry
A special loot room, an armory and a door locked from inside are not automatically the same lock type. Police Stations contain military supplies and locked armories. If a door says it is barred from inside, look for another entrance instead of assuming an unrelated key is missing. Compare the room name with the item text before consuming or discarding a key.
Acquisition and evidence limits
The official guide describes Lieutenant-related keys, but does not establish a complete named key directory or guaranteed spawn table. Plan around the key you actually own. Keep valuable keys in the Stash until the matching objective is ready, and use the Hajin directory to assess the destination.
Sources & version
Source review: October 22, 2026. Official key-grid guidance · FOB inventory