Recreating these scenes so realistically has to affect these kids emotionally, psychologically and even physically (due to the stress and anxiety). I wouldn’t be surprised if it caused mild PTSD.
Using children under the age of 18 is unethical at best; more accurately, it’s abusive.
Perhaps even more concerning: Where are the parents? Surely they had to sign to approve their kids’ participation. What mindset are the parents in that they allow their children to be used in such a way??