Note that you don’t have to actually SAVE the slaves, just as long as you get a slave outfit off of one of them. Why pay when you can save some good money by killing a few Slavers? And since you’re going to have to kill them all anyways if you don’t pay… deal with it in the most logical way. Third, pick the lock to the slave pen, which also involves having to kill the Slavers once you’re done. Second, steal the key from Ramsey, although once the slaves get out you’ll have to kill the Slavers.
First, kill everybody around and grab the Slave Pen Key off of Ramsey. Head west until you find the Train Tunnel, around which several Slavers are waiting with their slaves safely chained up. It’s not unique in the grand scheme of things, but new garb is always welcome, even if most of it is just edited Leather Armor and Metal Armor. You’ll notice some of the Pitt Raiders have some new Raider armor on them, unique to the Pitt. To do this, you will need to disguise yourself as a slave by interrupting a slave deal over to the west. Long story short, he needs your help to seize some cure to heal his people and overthrow the ruler of the Pitt, Ashur. Help him (or not) and afterwards he’ll talk to you. When you get close enough Wernher will get attacked by several Pitt Raiders. Turn on Wernher’s Distress Signal and fast travel to SatCom Array NN-03d, or somewhere nearby and head north to find the broadcast tower Wernher is using.