|Side Quest: Stop Gizmo|
|Complete Get Gizmo's confession quest.|
|Tell Killian about Gizmo's plans.|
|Speak to Lars.|
|Kill Gizmo and Izo.|
|Reward: 600 XP|
To start this quest, the Vault Dweller first needs to complete Get Gizmo's confession. Once the confession is delivered, Killian Darkwater will offer them the option to join him in taking out Gizmo. Should the Vault Dweller accept, they will be directed to Lars. Once Lars has been spoken to, the Vault Dweller will be immediately transported to Gizmo's office, together with Killian and Lars.
Gizmo and his bodyguard Izo will immediately attack, so the Vault Dweller has no choice but to battle them and kill Gizmo. Once they have been killed, the unique 9mm Mauser can be found on Gizmo's corpse.
If the Vault Dweller refuses to go when asking Lars, the quest fails. However, it is still possible to fight Gizmo and Izo. The other guards won't enter the office.
- Sometimes after talking to Killian when Kenji shows up, he will not attack Killian. This prevents the quest from starting and so the rewards cannot be obtained. There is no known way around it.[verified]
- Once asked by Killian to record Gizmo's confession, the player character can immediately talk to Lars and fight Gizmo without getting a confession. Killian will also be there and Lars will reward the player character the same amount.[verified]