Escaping on a Vehicle
Because vehicles have a top speed that’s far faster than most creatures can run, creatures in a vehicle can usually escape from a battle with enemies who are on foot, if they want. The GM has final say on whether a vehicle can escape. Usually, once a vehicle is beyond the range that the enemies on foot can run, those enemies get one more volley of attacks, and then the vehicle and everyone on it escapes. However, if the enemies also board a vehicle, they can usually pursue and the battle transitions to a vehicle chase (see page 282).
Source
Core Rulebook pg. 281