No one is going to want to stay behind a vehicle that is being shot up with 223...trust me. They would be seriously maimed or dead if they stayed.
You should go to the Hernando gun shoot next year and watch the live fire against cars. Most people watch the M2's and the MG42's. But pay attention to the guys with the AR's and what the results are when used against a vehicle in terms of anti-personnel effectiveness. I am always amazed at what that round is capable of...I have always wonder why that round is so disparaged when it is so dang effective.