Instead, maybe set it in the desert or a less populated place where there aren’t taxis. That way, the lady can just steal a normal car and the person who she stole it from was greatly affected/killed. The person who was affected could be the boss (I think that is a great idea that you had and it will be more believable in a less populated area). Maybe even the boss needed the car because he/she was running from villians? It could turn into a great, suspensful story. Have fun with it!

It illustrates the point of karma. How can one little, seemingly irrelevant thing come back to bite you? Its a thinker.

I don’t know if the effect should be so drastic though. I think you can manipulate things to make it more intense, and more realistic. Like she gets the job, but the bosses wife dies by some simple complication. Use minute twists through out it, not big events. That way, when everything comes together at the end, the reader realizes what happens and the story is sold.