Getaway driver (spoilers)

Let me get this straight, I enjoyed the film and definitely think the ratings have been tampered by trolls. Having said that, there seem to be some plotholes than need discussing.

If the pregnant woman was in cahoots with Vaughn and the robbers were in fact led to the bus on purpose, what would have happened if the getaway driver had decided to stay insead of driving off after panicking? How would Vaughn convince them to get on a bus instead?

Also, how did Derrick found such driver so quickly? The guy found him and his girl in a drughouse in a heartbeat.

Anybody else bothered by this?