What I do is go into the room that is at the end of the hall on the left as soon as you leave your cell. I choose to get found out and have the alert on so I can CQC all the guards in succession and knock them all out. There's a room in the middle (thats located behind your cell, you have to exit the cell turn left, and turn left again) that opens up all the cell doors. Press that button. There's also a room that has fulton balloons so you can fulton the guards you CQC'ed and also the POW in one of the cells. After that, head to the door thats to the 'northwest' I think it is of the room and you're in the clear.