Deep Vault 406 is a Legendary keycard in MW4 DMZ for X01, the Season 1 black site. Like the other gold three-digit Deep Vault keycards it does two things. It opens the X01 Deep Vault gate without being used up, and it unlocks Room 406, a lab with four safes on level 4 of the Deep Vault, grid D2 on the Data Center floor. Below is where the door is, how to get the card, the route down and what we found inside.
- Room 406 is on level 4 of the X01 Deep Vault (D2), right under Room 106 on the tac map. Ride the elevator behind the Deep Vault gate down, take the stairwell down to the painted 4 and follow the hall with the railing to the door with the 406 plate.
- The keycard opens the Deep Vault gate without being used up. Room 406 does use it up, just like Rooms 106 and 301.
- It is field loot and keycards roll randomly. We found ours on the desk in the X01 Executive Room.
- 4 safes with at least $28,900 in loot in our opening, plus a Legendary SR-16 Bio Agent Sample ($4,500) on the lab table.
- Worth it. Our first opening was not that great, but with four safes the room should usually pay off well in valuables.
Where the Room 406 Door Is
The Deep Vault is the long wing in the northwest of the X01 Data Center floor, from grid D3 up to C2 on the tac map, with the round Deep Vault gate at its southeast end. Room 406 is not on that floor. It is on level 4, the level with the big painted 4 in the stairwell, three levels below the lab level with Room 106. On the tac map it sits in the middle of the wing, grid D2, right under Room 106, and D2 is also the grid on the keycard tooltip.
From the stairwell, a hall runs along a railing on level 4. Room 406 is a double door on that hall, with a dark plate with the number 406 on the wall to its left and the card reader on the wall to its right. The light at the door turns red when it unlocks. The door is also on our interactive MW4 DMZ map under the X01 keys layer.
Click to enlarge The Room 406 door with the 406 plate on the left and the card reader on the right, right as it unlocked (brightened). 
How to Get the Deep Vault 406 Keycard
Deep Vault 406 is field loot, and keycards roll randomly, so there is no fixed spot to farm it. We found ours on the desk in the X01 Executive Room, and one lay on that desk in all three of our openings of the room. The game labels it a key in the tooltip, worth $100.
The gold three-digit Deep Vault keycards all work the same way. Each one opens the Deep Vault gate and its own room further down, like Room 106 on the Deep Vault 106 keycard and Room 301 on the Deep Vault 301 keycard. The gate does not use the card up. Room 406 does, just like Rooms 106 and 301. Our card was in the secure slot after the ride down and was gone when we opened the first safe, before we had looted anything, and the loadout value had dropped by the $100 the card is worth.
To get into X01 you can pick it straight from the FOB deploy menu, as its own location with Free Roam, and you spawn inside the facility. Our X01 entrance guide covers the ways in, and every key on Hajin is in our MW4 DMZ keys guide.
The Route to the Door
- The Deep Vault gate. On the Data Center floor, follow the wide corridor northwest past the Deep Vault sign into the wing. The gate is a big round vault door at the back of a hall with crates, with a card reader on the wall next to it. A gold three-digit Deep Vault keycard opens it and stays in your inventory.
- The elevator and the stairwell down. Past the gate is a room with an elevator. Ride it down, then take the stairwell down past the big painted 3 to the landing with the big painted 4. That is level 4.
- Room 406 along the railing. From the painted 4, go around the corner and follow the long hall with the railing on your left. Room 406 is the double door on the right with the 406 plate next to it. Swipe the keycard at the card reader on the right of the door.
Click to enlarge The level 4 landing with the big painted 4 (brightened). 
The Deep Vault goes on past these levels. The Core Room and Blix, the target the X01 orders send you to kill inside the Deep Vault, are further in. This page sticks to Room 406.
What Is Inside Room 406
Behind the door is a lab lined with lit glass terrariums, in yellow light, with a long table in the middle full of red trays and a big yellow lamp. The containers are four safes, under the windows and by the lab benches, and we found nothing else to open. One loose item lay on the table in the middle.
Containers
The containers decide the loot. Tap one to see what it can drop in our loot data.
Loot
-
SR-16 Bio Agent Sample Legendary $4,500 Loose in the room -
Animal Trial Records: R-4 ×3 Rare $3,000 each Safe -
R-4 Bio-Compound ×4 Rare $3,000 each Safe -
Encrypted Archive Rare $2,000 Safe
From one opening in our own run. Loot is random, so your room can roll differently, and we add every new run of this key. Values are per item, from the in-game tooltips. The loot value adds up every item with a known value and the cash, so it is a lower bound: crafting resources and items without a value are not in it.
The first safe held two Animal Trial Records: R-4 ($3,000 each) and $300 in cash. The second had an R-4 Bio-Compound ($3,000) and $750. The third gave another R-4 Bio-Compound, an Encrypted Archive ($2,000), one more Animal Trial Records: R-4 and $50. The fourth held two R-4 Bio-Compounds and $300. The best find was on the table, an SR-16 Bio Agent Sample worth $4,500, a Legendary ingredient for the X01 3D Printer. That adds up to at least $28,900 in the room, with Rare valuables and cash in all four safes and no Epic item.
Click to enlarge The terrarium lab behind the door (brightened). 
Click to enlarge The first safe with two Animal Trial Records: R-4 and $300 (brightened). 
Click to enlarge The SR-16 Bio Agent Sample on the lab table (brightened). 
Is the Deep Vault 406 Keycard Worth It?
Yes. Room 406 has four safes, and in our opening every one of them held valuables.
Our own first opening was not that great. The safes gave Rare lab valuables and some cash, with no Epic item. But with four safes in one room, Room 406 should usually pay off well in valuables. And like the other gold Deep Vault keycards, the card also opens the Deep Vault gate.
Our other X01 keycard pages cover Deep Vault 106, Deep Vault 301, the Executive Room, the Audit Room, the Small Test Chamber, the Maintenance Room, the Superintendent’s Office and Lt. Chol-Min’s Stash Room, each with its route and loot.
Frequently Asked Questions
Where is Room 406 in the MW4 DMZ Deep Vault?
On level 4 of the X01 Deep Vault, grid D2 on the Data Center floor. On the tac map it sits in the middle of the Deep Vault wing, right under Room 106. Go through the round Deep Vault gate, ride the elevator behind it down and take the stairwell down past the big painted 3 to the landing with the big painted 4. Go around the corner and follow the hall with the railing. Room 406 is the double door with a 406 plate on the wall to its left and the card reader to its right.
How do you get the Deep Vault 406 keycard?
It is field loot, and keycards roll randomly. We found ours on the desk in the X01 Executive Room, and one lay on that desk in all three of our openings of the room.
Is the Deep Vault 406 keycard used up?
Not at the gate. Like Deep Vault 106 and 301, it opens the X01 Deep Vault gate and stays in your inventory. Room 406 does use it up, just like Rooms 106 and 301. Our card was in the secure slot on the way down and was gone at the first safe, before we had looted anything, with the loadout value $100 lower.
Is the Deep Vault 406 keycard worth it?
Yes. Room 406 has four safes. Our own first opening was not that great, with at least $28,900 in the room and mostly Rare lab valuables and cash in the safes, but with four safes the room should usually pay off well in valuables. The card also opens the Deep Vault gate.
