 CONT: When fighting with the criminal in the fake armored car near  the beginning, the criminal fires a round at the window. It doesnt  leave a hole, showing that it is indeed bullet proof. A few seconds  later, Riggs slams on the brakes, and the criminal flies through the  same window, shattering it. Also, later in the film, it is said that  the bullets in the armored car suspects gun were armor piercing, so  it should have gone through the window.