Having them stop and get out using the car for cover would have been good if you would have had your pistol. However, I feel you did what you thougth was necessary and it turned out to be the right course of action. There's tons of "what if's" but your actions may have very well saved their lives and the lives of others. My hat's off to you......takes a man with balls of steel to stand in front of an agressor in a vehicle. My advice......learn from this and don't beat yourself up over what you could have or should have done. You did well and I'm sure your family thinks so too.
Church parking lots......great place to snatch and grab. Lots of people expecting to go preach the word of God who go in wearing nice outfits, lots of jewelry and leave their pistols at home or in the car thinking it will "Never hapen to them".