|Side Quest: Free Ghoul prisoner|
|Unlock the the ghoul's cell.|
|Speak to the ghoul.|
|Reward: 500 XP|
The Vault Dweller can unlock the cell and ask the inhabitant about where the water chip would be kept. Conveniently, the entrance to the vault where it resides is right next to the ghoul's cell. Experience is gained as soon as he is spoken to.
Killing the prisoner after letting him escape results in -1 reputation.
If you talk to the ghoul prisoner before killing the super mutants and then leave the area without freeing him, he will only say "Thank you again." if you return even if you have not unlocked the cell yet, making the side quest impossible to complete.[verified]