David O'Bannon was instructed by the agents at Hawkins National Laboratory to report the discovery of the deceased Will Byers in the quarry and not to let anybody get too close to the body. With the help of another trooper, he fished Byers' fake body out of the water. After this, he was mentioned and appeared on the local news.
Police Chief Jim Hopper questioned O'Bannon in a pub about what happened, but he refused to answer and walked away. Hopper attempted to resort to violent intimidation and got little information out of O'Bannon, who refused to say who he was working for and told Hopper he was "going to get [them] both killed" before running away.
It is unknown if O'Bannon faced any consequences for revealing the information he did.
Behind the scenes
O'Bannon's name is a reference to Dan O'Bannon, the screenwriter of Alien and co-writer, editor, and actor in John Carpenter's Dark Star. Both Alien and Carpenter are major influences on the Duffer Brothers and Stranger Things.