Ross was a member of the Colonial Marshal Bureau on Sevastopol Station. When a lone Xenomorph was unleashed on the station by the crew of the Anesidora in 2137, Ross and his fellow officers struggled to keep order. He ultimately left the team and became one of the survivors desperately waiting for rescue.
Ross was later shot by Clark when the latter had mistaken him for the Drone. Though he survived, he was badly wounded. Ironically, the actual Xenomorph showed up seconds later, presumably either capturing or killing Ross.
Renegading from the Marshals
During the Xenomorph infestation and subsequent loss of authority aboard Sevastopol, Ross figured he would have a higher chance of survival if he renegaded from the Marshals, and ultimately went through with his plan. His betrayal was later mentioned in passing by Waits; when officer Turner refers to the team's hunt for the Drone as a "fool's errand", Waits berates him and rhetorically asks if he wants to "run off like Ross".
Mistaken for the Xenomorph
Ross was exploring Habitation when he encountered Clark, who mistook him for the Xenomorph and shot him twice in the chest with his Revolver, killing him. Clark broke down upon realizing he had killed another human being, but upon regaining his composure took Ross's satchel of firearms, reasoning that he wouldn't need them anymore.
After recovering Ross's dropped weaponry, Clark walked over to Elevator C-3 in the hallway. Just as he was about to enter the elevator, Ross awakened and weakly begged Clark to help him. Clark turned around, shocked at Ross' survival.
In a cruel twist of fate, the actual Drone showed up behind Ross, who began crawling toward the elevator in terror and shouting at Clark to not leave him. Panicking, he ignored Ross' pleas and entered the elevator, hearing Ross screaming as the doors closed behind him. The Drone then attacked the helpless Ross and either captured or killed him.
- Alien: Isolation (comic)