The player may read Reilly's terminal to find that Brick has had a few violent run-ins with the Talon Company. Reilly states that this time she was able to calm Brick and brought her away from the argument. Reilly also says that she was unable to do so on a previous occasion which ended up with Brick unloading Eugene into many Talon Company Mercs.
The player can obtain Eugene as a reward for completing the Reilly's Rangers Quest. You have a choice of either Eugene or the Ranger Battle Armor. You can obtain both if you allow Brick to die during the quest and then loot her body. Alternately you can try to pickpocket Eugene from her, although be warned, you only have a very slight chance of this succeeding.