I have done some weapons training as am also ex military but I do know enough to maintain the advantage and keep inside a locked vehicle that still has the ability to travel. If it were that the idiot is that intent to get at me, he may break toughened glass but that takes time and draws attention and should someone get in, well inside a camper there are plenty of tools to help the situation, included in mine was two and a half litres of BCF goodness to take the oxygen out of an assailant's air when it is discharged in their direction, then out the sliding door and away, by which time it would be hoped the police might have received sufficient calls to have taken an interest, especially so as the incident occurred less than a mile on a straight road from the cop shop. But having pushed the offending car out of the way I drove down to the cop shop and reported the incident.
Oh the reason I did not reverse out of the situation was because myself being stopped by a car angled across the lane in front of me, not only stopped me, but everyone travelling behind me the only way was forward and campers are pretty tough machines with a chassis of sorts and one hell of a C section steel bumper, not as wieldy as say a land rover bumper, but enough to take on cars.
Now I have a clio, any problems, it's dark green, I can go and hide in a bush, but I have been living down here for seven years now and I can quite honestly say the levels of road stress I encountered up that way near London were terrible, down here they may drive fast, but they are not particularly aggressive with it.