It's just plain old physics at work there, SwamP_ThinG.

When you get hit in the head by a high-velocity projectile the majority of the contents of your skull will always eject outward in the direction that the bullet came from.

That's caused by the "cavitation" effects of the high-velocity projectile itself. The high-velocity object pushes everything away from itself with great force - it imparts a portion of it's own inertia (kinetic energy) to whatever it comes into contact with, pushing any surrounding material away from it's path very forcefully. Since this all happens in a nanosecond, as the bullet is still traveling through the skull, initially the only place the liquified material, which is under great pressure from those kinetic forces imparted by the projectile, can escape the skull is through the original opening - the first bullet hole, in other words. Some of the material (a realtively small amount) gets sucked into the vacuum vortex that the fast-moving object creates behind itself, and when the bullet finally reaches the other side of the skull and exits this "pulled along" material is ejected from the second hole. But by that time most of the material has already been blown out the first hole by the vast internal pressures of high-velocity cavitation.

http://www.vnh.org/EWSurg/ch02/02Discussion.html

On the helicopter video: It's hardly murder when it's obviously a perfectly legitimate engagement against hostile forces in the middle of a war. Those guys on the ground were willfully engaged in hostile actions against the forces that killed them. If they didn't wish to be killed in that way then all they had to do was not engage in those hostilities.

A wounded soldier may still be able to fight despite their wounds. It happens all the time. They might also be treated medically, recover, and rejoin the fight later. There is no legal mandate that demands that you do not fire on a wounded combatant, unless they are actually (and truly) attempting to surrender. Those guys were not attempting to surrender. The pilots could not even be sure that guy had been hit yet. You can't be sure either, not with any real certainty, not having actually been there to inspect him physically yourself.

I think it's moot. If you fight in wars it's assumed that you're fully prepared to die as a consequence of your involvement. They fought, they died. Their choice.

Personally, I think that guy was hit the first time, and I think that had they left him alone at that point he would have suffered a long, hard, excruciatingly painful death, alone out there. I think they actually did him a huge favor by administering the swift coup de grace as they did.