Rivet City has contracted with the Brotherhood of Steel to help escort water caravans to their destination, in exchange for getting money and technology from the Brotherhood. Officer Davis is one of the security team hoping to be paid with technology.
If he survives the bandit ambush, Davis will travel back to Rivet City to report to Officer Lepelletier. After Davis speaks with Lepelletier, he will disappear as soon as the player leaves the active map cell. Davis has no dialogue tree, and will simply thank the player for saving him if spoken to.