You find the loose brick in cell 295, and pull it out from the wall. Inside is a glowing box, and a piece of parchment. It says:
I, Enrick, hid this treasure away from my captors in the hopes that it would help some other Seeker escape this terrible place.
As for me, I am tunneling out tonight, in the hopes that by the time someone finds this letter, there will be no more need for rebellion. I go to reinforce the Forest Rangers at the Northern Outpost, to stop Zeruul’s southward march.
Long Live the Rebellion,