Part of a caravan heading into New Vegas, he along with the rest of the survivors (Carter, Dennis and Rachael) were taken prisoner by the Fiends. They were taken to Vault 3 to be held for ransom, however unbeknownst to the Fiends, anyone who would be willing to pay such a ransom died in the attack. Thankfully the Fiends' haven't found this out, otherwise they would've just killed the rest of the prisoners. During their imprisonment one of their own, Carter, managed to escape and explore the Vault before being captured and brought back to the holding cell. Although Carter would die in that pen, the password he hacked and the weapons he found was relayed to Rick. Rick with this information, along with the information that they keys for the cell on a fiend named Daniel, will offer it as an incentive to the Courier to help them escape.
He will tell you that his friend Carter snuck out of the cell and went exploring the vault and found a password for a room filled with weapons and he was heading there before he was killed by the fiends.
↑The Courier: "I need to know a little more about Vault 3." Rick Lancer: "I don't know much, only that the people who lived in here originally were killed by the Fiends. Carter there escaped and managed to explore for a bit. He hacked a password off of the computer, and found the location of some guns. He was on his way to get them when the Fiends caught him again." (Vault3Prisoner01.txt)
↑The Courier: "What are you doing here?" Rick Lancer: "We were part of a caravan heading into New Vegas from down south. They are holding us hostage, trying to get some ransom. Anyone willing to pay for us died in the attack. Once the Fiends figure that out, we are as good as dead. Can you set us free now?" The Courier: "Yeah, I'll see what I can do." Rick Lancer: "Thanks partner. I think the Fiend with the key is back in one of the bedrooms somewhere, someone called him Daniel. If that helps." (Vault3Prisoner01.txt)
↑The Courier: "Can you tell me about the Fiends?" Rick Lancer: "They are a bunch of junkies that do whatever they can to get money for chems. I hear they are lead by a guy calling himself Motor-Runner. I think he is in one of the other wings, although I haven't seen him myself." (Vault3Prisoner01.txt)