if the guard is repeatedly firing regardless of the fact that there's someone standing in front then it's the guard's fault, he should be punished
if there are prisoners using themselves as meatshields to block such person, they shouldn't be ressed as it's their fault
if a prisoner does something illegal and hides in front of their teammates and the guard doesn't realize that the shield is lethally close to his target then it's nobody's fault, the prisoner gets ressed and things move on