“Under threat of fire...”
Many who are trained would not do as well.
He heard a gunshot behind him, turned around, stumbled, and shot attackers.
Good kill
You are correct. However, this incident has no military merit on any level.
In My experience w/ troops in contact you may be surprised at how confident and composed most are when being bloodied.
Training and more training. I would suppose young Kyle has a bit of combat drilling with an AR under his belt.
The only fault I can see is no battle buddy present.