When you reach Moonrise Towers, head up the first set of stairs, then through a door on the right and down a small staircase to the prison. Inside the prison, there is:
- 1 Warden
- 1 Stationary Guard (west side)
- 2 Patrolling Scrying Eyes
- 1 Patrolling Guard
Enter the Warden’s office and wait for a scrying eye to enter. Then, switch to turn based mode (Shift + Space), dispatch the scrying eye, and finish off the Warden. Work your way to toward the beginning of the prison (east entrance) and wait for the last scrying eye and the patrolling guard to show up, taking both out. Once they are dealt with, you won’t need to worry about the stationary guard.
Now, talk to the gnome in the prison cell, Wulbren, and throw an bludgeoning weapon (mace, flail, etc.) in so they can break out the back wall and free the teiflings. After all the prisoners run out the back, go into the warden’s office and flip the 2nd and 4th levers on the wall to open the cells, giving you a path to meet them at the boat. Do not flip the switch on the floor, since it will sound an alarm. Either accompany the prisoners to Last Light Inn, or tell them you will meet them there. After the boat leaves the dock and floats away safely, the achievement will pop.