You have to do rescue Cassie ending, you can use wiki to help you through, but you just have to choose option grunt work when you say you don't want to pay the 200 credits, and after you say you will work, Don [tip just push or trick the guard that you have to pay 5 credits to get in the Slums], this is like 1/3 parts you have to do, Wiki explains way more and is easier to read.