In all honesty Optimus Prime is not supposed to be "stone cold killa" he is supposed to rise above, however Im referring to the sadistic nature he seems to execute people with. Even in a time of war that by military law would be considered a war crime. When the enemy is beaten and cant fight back there is a difference. Sentinel would have probably died on the spot anyway putting the bullets in the head is just sick and if you think its justifiable you got issues. There is a differance between being good guy and a bad guy right or am I missing something. The good fight has a moral it fights for and doesnt cross it or they just become the same as the bad guys and then its not about morality its about who wins essentially.