I just have to back up this post. You can not physically,mentally or emotionally prepare yourself for this type of stuff because there are no written guidelines when you go to war that states this and this is going to happen on such and such a date things in that perspective happen at the spur of the moment.
Not trying to threadjack but if you want a true example of something unpredictable check out the thread that i posted it will give you an insight to how quickly things can escalate in the line of duty.
http://www.stevemeadedesigns.com/board/topic/83943-some-decisions-are-never-easy/