You can look at all the prisoners, but little easter eggs and hints aside, there's not much in each containment cell. The only prisoner of note is Berkana, whom you can interact with. You have to go down to the third level and fight a boss, then read whichever scroll you choose into a big inter-connective megaphone thing. If you plan on following Llengrath's suggestion, remember to help Berkana first, otherwise she dies as well.
I chose Llengrath since I could get all the loot. You also unlock a special quest that only shows up if either of the two Archmages like you enough. If you do Tayn's bidding, you will disperse the prisoners' memories randomly and also have to screw over Llengrath later.