Soldier F would only have to prove that he reasonably believed that there were armed terrorists in his sight. The onus on the prosecution is to prove guilt beyond reasonable doubt.
In England there have been several cases where armed policemen wrongly but reasonably believed that their lives were under threat when they opened fire and were thus acquitted.
Are you saying killers should use case law in order to walk.....ie “your honor there was a killer in Hicksville who was bit in the arm by her attacker and he walked, same happened to me”
FFS Dave, go for a lie down or something