Call of Duty: Modern Warfare 4 DMZ Operation Grid Assault Story Mission Walkthrough

Operation Grid Assault is a DMZ story mission in Call of Duty: Modern Warfare 4. It takes place in The Grid, the downtown block around DBN Headquarters and Hanex Bank, and both buildings are marked THREAT: EXTREME. Most of the work happens inside DBN Headquarters and on its roof, with one trip across the street to Hanex Bank.

Quick answer: Take a hash key half from Hanex Bank, kill Lieutenant Roze atop DBN Headquarters, hack the floor 10 laptop, defend the rooftop antenna upload, then broadcast from the top of the lattice tower.

Operation Grid Assault objectives in order

The HUD lists the objectives under “MISSION: OPERATION GRID ASSAULT”. Each one switches to the next as soon as you finish it.

#	Objective	Location	What finishes it
1	Find the Drone Control	DBN Headquarters, upper floor	Reaching the marked rooms
2	Get the First Code Segment	Hanex Bank, upper floors	Collecting the hash key half
3	Get the Second Code Segment	DBN Headquarters, broken upper levels	Killing Lieutenant Roze
4	Compile the Code	DBN Headquarters, floor 10	Hacking the laptop
5	Upload the Code	DBN Headquarters roof	Defending the antenna
6	Broadcast the Kill Code	Top of the rooftop lattice tower	Sending the broadcast

Killing Roze also completes an optional side op, KILL ROZE, which runs alongside the main objectives.

Operation Grid Assault walkthrough

You infil at the edge of The Grid, at street and basement level next to DBN Headquarters. The RADIATION COUNTDOWN starts at about 30:00, so keep moving between objectives.

Find the Drone Control and the first code segment

Enter DBN Headquarters and ride the lift up with the “USE ELEVATOR – ASCEND” prompt. Clear the soldiers in reception and the upper corridors.

Follow the mission marker to the marked rooms on the upper floor. Arriving there switches the objective to Get the First Code Segment.

Outside route: DBN Headquarters can also be climbed from the outside. After the lift, go out through a window onto the yellow window-washer platform on the facade, then use ASCEND on its cable to reach the roof. The rooftop helipad has a radio terminal with an ENTER ACCESS CODE keypad. A COMMANDER DEATHSTALKER attacks the helipad as soon as you get there, so arrive with a scoped rifle ready; steady fire into the cockpit brought it down in about 25 seconds, with the DESTROYED DEATHSTALKER COMMANDER banner on the kill.

Take the lift back down with “USE ELEVATOR – DESCEND” and cross the street to Hanex Bank. Ride its lift up to the office floors.

Fight through the police riot-shield guards, their shields marked 경찰, and the armored soldiers holding the corridors and stairwells. You can ignore the door with the “ENTER ACCESS CODE” prompt, since the mission does not need it.

Climb the stairs to the marked target and kill the riot-shield escort along with the target. Smoke helps you cross the open stairwell on the way in.

Use the COLLECT prompt on the drop, “HALF OF AN ENCRYPTED HASH KEY”, listed as a MISSION ITEM. The objective changes to Get the Second Code Segment.

First encrypted hash key half — The first code segment is a mission item dropped by the target high in Hanex Bank. Shown at 06:59 in TheGamingRevolution’s video. Image: Infinity Ward

Kill Lieutenant Roze for the second code segment

Head back to DBN Headquarters and climb toward the top. Use the lifts first, then the ascender cables in the shafts and stairwells with the ASCEND prompt.

Near the top, the building is broken open on the outside. LIEUTENANT ROZE fires a rifle from the damaged upper stair landings, backed by regular soldiers, and a COMMANDER DEATHSTALKER banner for an attack helicopter appears around the same time.

Hold cover by the breach and focus your squad’s fire on Roze. The kill shows SIDE OP COMPLETE / KILL ROZE, and the objective moves to Compile the Code.

Lieutenant Roze on DBN Headquarters — Lieutenant Roze holds the broken upper levels of DBN Headquarters during the second code segment step. Shown at 09:36 in TheGamingRevolution’s video. Image: Infinity Ward

Compile the Code on floor 10

From the high ledges, deploy a parachute to get down quickly, then re-enter DBN Headquarters and go up to the roof.

The Deathstalker hits the roof with gun runs and rockets. Stay under the roof canopies and shoot it as a squad until the DESTROYED DEATHSTALKER COMMANDER banner appears.

Deathstalker over DBN roof — The attack helicopter makes runs over the DBN Headquarters roof; the canopies give you cover while you shoot back. Shown at 11:50 in TheGamingRevolution’s video. Image: Infinity Ward

Loot the HELICOPTER PIECE containers in the wreck if you want. The legendary item inside is a PROTOTYPE RF MODULE.

Drop down a cable shaft to floor 10, marked “10 ENTRANCE” on the wall, and clear the soldiers there.

Find the laptop on a desk in the control room and use “HOLD TO HACK”. Once it reads ALREADY HACKED, the objective changes to Upload the Code.

Hold to hack laptop — Hacking the laptop in the floor 10 control room completes Compile the Code. Shown at 13:53 in TheGamingRevolution’s video. Image: Infinity Ward

Upload and broadcast the kill code

Go back up the cable shaft and the stairs to the roof. The antenna unit sits in a rooftop enclosure beside cylindrical tanks.

Interact with the antenna. The game shows “UPLOAD STARTED. PROTECT THE ANTENNA UNTIL IT FINISHES.” and a BROADCASTING CODE bar begins to fill.

Upload started at rooftop antenna — Starting the upload at the rooftop antenna begins the defense phase. Shown at 14:33 in TheGamingRevolution’s video. Image: Infinity Ward

Stay near the antenna while armored reinforcements climb onto the roof and a second COMMANDER DEATHSTALKER arrives. A sniper rifle such as the Astaroth .50, or steady rifle fire, brings the helicopter down.

When the bar fills, the game shows “UPLOAD COMPLETED. SEND BROADCAST.” and the marker moves to the top of the tall lattice tower on the roof.

Send one squad member up the tower to the marker to send the broadcast while the others cover the roof. MISSION COMPLETE / STORY MISSION appears a few seconds later.

Enemies and bosses in The Grid

North Korean soldiers, armored soldiers, and police riot-shield guards hold both towers.
LIEUTENANT ROZE fights on the broken upper levels of DBN Headquarters and pays out as a side op and a lieutenant takedown.
COMMANDER DEATHSTALKER is an attack helicopter over the DBN Headquarters roof, with one during Compile the Code and another during the upload. One can also hit the helipad the moment you first reach the roof by the outside route.
Deathstalker wreckage holds loot such as PROTOTYPE RF MODULE, NITRO COMPOUNDS, BIOMATERIALS, and REACTIVE METALS.
COMMANDER COLOSSUS patrols The Grid with heavy fire and support troops but is not a mission objective.

Downing a Deathstalker can also pop a CHALLENGE COMPLETED banner for “ELIMINATE 5 COMMANDERS”.

Exfil and Operation Grid Assault rewards

The MISSION COMPLETE banner does not extract you. You still need to reach an exfil and leave The Grid, and Commander Colossus roams those same streets on your way out.

If your squad is wiped before exfil, you get FAILED TO EXFIL / MISSING IN ACTION, though the mission payouts still appear in the EXTRACTION SUMMARY.

EXTRACTION SUMMARY line	Amount
Story Mission Payout	5,000
Side Ops Payout	500
First Lieutenant Takedowns	10,000
BANKED CASH	15,500

Payouts after failed exfil — Story mission, side op, and lieutenant payouts still land in the extraction summary after a failed exfil. Shown at 22:46 in TheGamingRevolution’s video. Image: Infinity Ward

Together, the story mission payout, the KILL ROZE side op, and the Roze takedown add up to 15,500 banked cash.