Edison Trent met Sam Lonnigan for the first time in the Sigma systems on Planet Kurile. In Trent's log, he describes Lonnigan as "a hired gun representing Samura Heavy Industries." Lonnigan was angling to purchase a shipment of Boron from Trent for a cool million credits, a deal which Trent failed to get paid for when Freeport 7 blew up. Lonnigan was hit in the head by collapsing debris during the attack; Trent carried him to the life pod. Lonnigan remained unconscious for several days during the journey to Planet Manhattan; however, medical personnel nonetheless seemed confident that they would revive him, despite his head injury and days of unconsciousness.
Trent sees Lonnigan conscious for the first time on Manhattan at the beginning of Mission 2. It's possible that his incoherent jabbering is the result of the head injury and/or drugs from his hospital stay. However, Trent's later comment to Juni implies that Lonnigan may not have been too bright in the first place.
He later appears again on Manhattan, this time appearing much more focused and determined (not to mention angry). He holds a gun on Trent for the entire conversation, and claimed to have killed a man to escape custody. He states a desire to escape Liberty entirely, and warns Trent that he should do the same.
We never get a chance to find out what Lonnigan's original angle might have been, because by Mission 3 he gets shot by security guys and Trent gets smacked in the chest with a stun baton and left on the landing pad. And that's the last you see of Lonnigan until his face shows up on a newscast claiming that the LSF has confirmed that Lonnigan is Orillion, and that he was shot and killed trying to escape Liberty. Trent scoffs at the idea that Lonnigan could have been Orillion, telling Juni that Lonnigan "wasn't smart enough to be a terrorist, let alone lead them". He instead considers this announcement to be just one more piece of evidence of conspiracy in Liberty.
It is likely that the deal with Samura that Lonnigan was fronting was a scam. No player-flyable ship holds more than 275 units of cargo. Even if Trent got the Boron free, the best price on the stuff is still only 960 credits per unit. For Trent to make a million credits on such a load, Samura would have had to pay nearly four times that, which is simply too good to be true. On the other hand, Trent was not a player character at the time, so he could have been driving a non-player-flyable ship such as a Train or Supertransport at the time.