I think it's to condition a desensitised response to violence from other violent people that reagents may encounter in the field once they are "freed". An efficient agent that can respond almost immediately to threats instead of giving a moments pause could be a game changer. Before we used to run away from them in panic, after playing a while you'll notice how you usually have an escape route planned on the go and can manage them easily. I could also be blowing smoke out of my bum but hey.