When Callen brings Sam a fresh beer, at the surprise beach party, Sam puts it down in front of the supposedly empty bottle after the first sip. But, every time he drinks beer thereafter, he reaches and sips from the first bottle _behind_ the second one.
Cars will not instantly explode from a few bullets. But, they will explode if hit with two grenades! And it was a remote-control grenade launcher, mounted on top of the M-60, that fired a couple retaliatory rounds at the car behind the two security guards.
Cars will not explode from getting hit by bullets.
The guards fire at the fleeing vehicle, but there's no driver, which means no one for their gunfire to hit.