Why do some cars get to pass the safety car before it finishes?

The safety carThe FIA runs the event and is responsible for the safety of the drivers, crew, marshals and spectators. To manage... is deployed to control the fieldThe field is a reference to the full grid of cars, from pole to the backmarkers. Consider it in the... There's more... while marshalsMarshals, dressed in their distinctive orange overalls, have a number of roles but the majority are positioned around the circuit... There's more... deal with an incident on track. Cars must follow in single file and may not overtakeAn overtake is when one car passes another. It sounds obvious but it is not as simple as that. The... There's more..., meaning that lapped carsWhen the lead car catches up to and passes the car at the back of the field it has been... There's more... are out of order.

Just before the safety car ends, the race director may allow the lapped cars to un-lapWhen a lapped driver manages to pass the car that previously passed him, then he is unlapped. Lapped drivers are... There's more... themselves by passing the safety car and rejoining the back of the field.