Fallout 4: Spoils of War Quest - Mass Fusion, Beryllium Agitator

This guide will help you complete the Brotherhood of Steel Quest: Spoils of War. Obtaining this quest means that you are most likely devoted to the Brotherhood of Steel and their cause. However, this quest provides one last opportunity to renounce your loyalty to the Brotherhood if you have had a change of heart.

If instead you needed help with anything else regarding Fallout 4, then be sure to head over to our Fallout 4 guides walkthrough hub, featuring a wealth of other quest walkthrough guides, as well as where to find every Bobblehead in the game.

Completing this quest greatly impacts the narrative and will define the events that unfold from here on out. If you are prepared to tackle this important quest, then continue to follow along with our guide below.

How to Complete the Spoils of War Quest

Speak to Proctor Ingram

Head over to Boston Airport and speak with Proctor Ingram. The lack of an adequate power source has caused her progress with Liberty Prime to come to a halt. She needs a device called a Beryllium Agitator, which can be found within the Mass Fusion building located in Boston’s Financial District.

After you agree to help Proctor Ingram find the device, she mentions that she plans to come with you. Decide whether or not you want Proctor Ingram to tag along, and then head outside to the flight deck where a Vertibird is waiting on standby.

Note: The Mass Fusion building poses various threats to your health, including irradiated rooms, defensive robots, and heavily armed Synths. It’s a good idea to bring along several types of healing supplies, such as RadAway, Rad-X, Stimpacks, and radiation-free food. If you have either a Hazmat suit or Power Armor available, consider equipping one of these as well.

Fly to Mass Fusion OR Inform the Institute

Proctor Ingram has arranged for a Vertibird to drop you off on the rooftop of the Mass Fusion building. If you agreed to have Proctor Ingram come along for the ride, she will join you on the gunship. Before you enter the Vertibird, you will have one last chance to switch your loyalty to the Institute. The choices are as follows:

• Board the Vertibird and fly to Mass Fusion. This makes you a permanent enemy of the Institute. You remain devoted to the Brotherhood of Steel, and will continue to complete this quest and other faction objectives to aid the Brotherhood's cause. Several Institute quests will instantly fail, and the Institute Quest: Banished from the Institute will begin.
• Don’t Board the Vertibird. Instead, exit the area and make a trip to the Institute. Inform them of the Brotherhood’s plans, and solidify your newfound loyalty to the Institute faction. This will begin the Institute Quest: Mass Fusion.

If you have decided to stick with the Brotherhood of Steel, then continue to follow along with this guide to complete the remaining steps in the Spoils of War quest.

Jump to Mass Fusion’s Roof

Take control of the minigun turret and prepare to open fire on a handful of Synths as the Vertibird approaches the rooftop of Mass Fusion. As the Vertibird hovers over the rooftop, disembark from the gunship and drop down onto the roof. Watch out for a Legendary Synth Patroller that may join the fight as well.

Locate the Beryllium Agitator

Proceed into the Mass Fusion building, eliminating the hostile Synths you encounter along the way. Go up the staircase to the second level, and locate the Executive Research Lab terminal in one of the rooms.

Retrieve the Executive Key Card

To access this Advanced level lab terminal, you must first find the password. Just outside of this room, look for a desk in front of a Mass Fusion sign. Inside the desk there is a Mass Fusion Executive ID card, and the lab password needed to access the terminal.

Read each of the personal intramails on the terminal to discover that the Beryllium Agitator is found in the basement. Considering you entered from the rooftop, you have quite a long way to go before you reach the bottom level.

Proceed to the Reactor Level

• Optional: Restore Power to the Elevator

The elevator seems like the best option to reach the basement level. Use the Executive Key Card that you found on the desk and swipe it in the elevator’s ID card reader. Going down!

Take a nice long trip down on the elevator, and prepare to fire a few shots at enemy Synths as you pass by each floor. Along the way, your elevator ride will be interrupted by a huge explosion, knocking out the elevator’s power. Be ready to fight off a slew of Synths that converge on your position. To restore power to the elevator, you can either head up to the circuit breaker, or hack the Expert level Manager’s terminal found in a room just beyond the elevator.

Restoring power to the elevator is optional, but doing so can greatly simplify your trek to the basement. To locate the circuit breaker, head through the doorway northwest of the elevator and continue through the doors until you reach a room on the second level containing the breaker box. Activate the circuit breaker, then hop back in the elevator to continue your descent. Hacking the Manager's terminal in the room west of the elevator will also do the trick.

Another option is to snag the Mass Fusion Labs key off the desk just beside the Manager's terminal, and use it to unlock the adjacent room. Drop down the hole in the floor, and make your way down toward the main lobby on foot.

Enter the Reactor Chamber

Once you reach the lowest level, prepare to enter the Reactor Chamber. The chamber will expose you to a hefty amount of radiation, so hopefully you came prepared. If not, Proctor Ingram will offer you some Rad-X. However, if you decided to leave Proctor Ingram behind, then you will have to just search the area for items to help ease the radiation poisoning prior to entering the chamber.

Enter the southwest hallway and press the button to activate the Mass Fusion Mainframe. Step into the decontamination area and wait for the sequence to run its course. Now, enter the Reactor Chamber, and move along the walkway to reach the top of the reactor.

Unlock the Reactor

Before pressing the Interlock Release, take note of a pair of laser turrets just above the reactor along the upper corners of the wall. Once you take the device, these laser turrets will shoot at you, so prepare to take them out. When ready, approach the reactor and press the Interlock Release.

Take the Beryllium Agitator

Once the reactor is unlocked, remove the Beryllium Agitator that you came for, and get ready to bolt out of the area. Exit through the same way you entered, initiating the decontamination sequence once more to unlock the door.

Eliminate Reactor Level Security

Taking the Agitator causes the facility’s automated defenses to activate. Prepare to gun down a Sentry Bot and Protectron as you enter the next room. Now is a good time to use a Fat Man or another heavy weapon you have handy to quickly eliminate the robot threats.

Use the Executive ID card to open the main door, and get ready to fight off a pair of Assaultrons. Defeat the defensive bots, and make your way up the stairs. Watch out for laser turrets and another Protectron along the way.

Exit Mass Fusion

• Optional: Assist Brotherhood forces in the Lobby

Continue up the stairs until you reach an elevator marked with an Exit sign. Ride the elevator to the main lobby, where you will find another wave of Synths attacking the Brotherhood reinforcements. You can head straight for the exit, or stay behind to help fight off the Synths if you wish.

Return to Boston Airport, Speak with Proctor Ingram

After leaving the Mass Fusion building, use your Pip-boy to fast travel back to the Boston Airport, where Proctor Ingram will be waiting for you. Chat with her once more to conclude this quest.