The line between heroism and tyranny

Everyone knows that violence is a part of our human nature. Since the age of caveman we had evolved through the progress combat from wooden clubs to iron spears and from muskets to full-auto weapons. Now in society today violence is seen as a taboo and the urge to kill another has been extinct for a long time. However in some cases we still have that urge to shed blood. So I asked a question to myself after the first terrorist attack faced in my country happened, What I did was I being a human or a monster? Little did I know that God had a little surprise prepared for me just a few weeks after.