McKenzie drove slowly, with the headlights on. She obeyed the speed limits and traffic signs. She drove carefully, but not so carefully as to look suspicious. When the police passed them, going in the other direction, they looked like any normal group of people driving around at night. They didn’t even get a second glance from the men and women in the patrol cars.

McKenzie took them slowly but surely out of the city. No one pulled them over. They weren’t questioned. Once ...