Every Little Decision

In the book every little decision counts. Do you turn left or right? What normally might be a simple choice could turn fatal right away. Not everyone follows the rules of engagement, one of the rules is to not fire or take a Red Crescent van (Red Crescent is like the USA's Red Cross; the vans are also used as ambulances). In the book there is one part were a Red Crescent van starts bolting forward toward the Humvees. What are the soldiers supposed to do, shoot or let it keep going because it could be an emergency? Marla is on the turret and decides to start open firing even though she is not supposed to. She made the right choice, it turned out the van was full of insurgents and they had RPG's and AK's. I think they were going to hop out and then the van would crash into the Humvees, but Marla gunned the driver down and saved all their lives. Every thing can mean life or death.