When Marshal Gonzalez is locked in the room at the U.S border patrol, there are a number of wanted posters on a board. One of these posters show a sketching of the Zodiac Killer, the real life serial killer who was never caught for killing 5 people in the San Francisco Bay Area between 1968 and 1969.
Scott is worried that the gun Richie is pointing at him in the RV will accidentally go off if they hit a pothole. A callback to Pulp Fiction when Vincent Vega accidentally shoots a man in the head after the car hits a pothole.