I agree with Sam's suggestions. Postworking dust with a paint proggy is the easiest way.

Why not have Mike leaning out of the truck door, one hand grasping the wheel and in the other a pistol, trying to get a shot at the thing? The truck's front wheels turned hard left and the truck slightly tipping to the right. That would make for a more dramatic scene showing lots of action and interest. Oh, and a horrified screaming damsel in distress too!  ; )

 Don't sweat the petty things, and don't pet the sweaty things!  ; )