10000 XP, Metal Kanabo
After finishing the Titus Andronikus quest, this one will start when you talk to Titus. Follow the mini-map to the cell. Then you'll need to go to the control room. One you unlock the cell quickly turn off the alarm on the other side because infected will keep spawning until you do. Get back to Alvaro's cell and escort him back. Talk to Alvaro for your reward and Titus for the Full Metal Jacket quest.