I didn't think this kind of stuff actually happens.  I see this type of training at Front Sight classes, but I never took it seriously cause it feels like one of those fantasy nightmare situations.

Robber was holding his wife at gunpoint — so husband aimed for his head, Texas cops say

He exchanged fire with the two men, forcing one of them to run, the station reported. But the one who stayed in the gunfight was holding his wife at gunpoint.

So police say the husband aimed for his head.

The husband shot the man who held his wife once in the head, injuring the man critically, but not killing him, according to KHOU. Police found the attacker lying in the couple’s driveway.

https://www.star-telegram.com/news/state/texas/article215081785.html

The first time I went through the shoot house at FS the instructor told me I got all the bad guys and didn't shoot any innocents, but all my shots were in the head.  He told me to put two shots center mass first, except for the one popup with the guy holding the hostage.

In real life it would be extremely difficult to pull the trigger to shoot someone in the head who is hiding behind someone you love.  Gotta give that guy a lot of credit for what he did.

I did the same thing. The instructor said, "You hit the guy in the clown mask in the head, but for all you knew, that mask was part of a kevlar helmet. You should have put 2 in the thoracic cavity as well, just to be sure."

I don't think you can get it right the first time through -- on purpose.  It's a teaching device.

I did like the exercise where we put our loved one's name on a hostage target and had to put 5 through the left side of the ocular-cranial area, then 5 on the right side.  Basically, you have to aim at an area less than 1/2 the size of the normal O/C target outline.

I got all 5 in the right side plus 4 inside and one about an inch outside on the left.  Didn't hit the hostage outline, so she survived.   

They should make you run sprints before shooting to make it more realistic.

I did the same thing. The instructor said, "You hit the guy in the clown mask in the head, but for all you knew, that mask was part of a kevlar helmet. You should have put 2 in the thoracic cavity as well, just to be sure."

https://youtu.be/MF06H5OHbQk?t=3m12s

Kevlar or not, they are still getting ~400 ft lbs of energy to the face assuming an average pistol round.  Orbit bones, teeth and eyes are not going to be happy with that.  unlike the movies I doubt anyone could take a round to the face with a kevlar mask and not be a tiny bit shook up. About the same energy as a 16 lbs hammer traveling 25 mph into the face. 

The first time I went through the shoot house at FS the instructor told me I got all the bad guys and didn't shoot any innocents, but all my shots were in the head. 

     Before I went in he said it was a "Hostage situation" and previous instruction was "Shoot hostage taker(s) in the head.
So I too placed all rounds on the bridge of the nose of all bad guys only to be "corrected" later.
I suppose I could have center massed the first guy as well as the one with a shotgun all the way down the hall, but the 2 bad guys around the corner, one with muzzle on hostage, the other muzzle pointed in direction of hostage... 

    There was a female student mom) who came out of the shoot house crying.
I asked her what was a matter and she said when she saw the child hostage at gunpoint, she just broke down emotionally, could not shoot.

As for naming my hostage, I used my favorite chickens name (Marilynn).   
She survived. 

The training I am familiar with is to get as close as possible before taking such a shot with a pistol. It is such a scary situation, even if I am confident I would still fear hitting my wife in the hear just given human reaction times.

The closer you get to your target, the more you make yourself an easier target.

If you can get the bad guy to point the gun at you, you have a better chance of a debilitating shot without him shooting the hostage, making your hitting the "kill switch" less critical.

Otherwise, with his gun on the hostage, you have to hit the "kill switch" to prevent him from squeeing the trigger. That's in the occular-cranial area from the front. If you miss, a hit to the side of the skull can glance off bone, or a shot into the mouth will hit teeth and thick bone, blocking the shot from a quick kill.

The downside of getting him to not have his gun on the hostage is the gun is now in your direction. If you are very close, as you said, the chance of finding cover to protect yourself is much slimmer.  If you're dead, you can't save anyone.

p.s.  Call of Duty isn't "training".