Would Pike have pulled the trigger if it not for the happy coincidence of gaining his memory back? (Doylist explanation being that the writers can't just have our highly esteemed captain straight up murder a guy). High Lord Zacarias begging for his life like a little pissant sure thought he was capable of it. Was Quark right? Starve humans of their desires long enough and they will be worse than the Klingons and Cardassians. It didn't take Pike very long to go fucking nuts!
Even Pike seems shaken at what his stance was when he came out of his amnesia.
Alternately, another interpretation of that scene I had is that when Humans do remember that they are supposed to be kind forgiving people, there is indeed a chance for redemption and it was kind of a nice juxtapose that the Zac knew he didn't have to goad Pike into pulling the trigger. Even when he's dejected and says that he's done a lot against his duties and the law, he was ready to face the consequences than cowardly escape them with death. Klingons want to "die with honour" but it seems like humans prefer to live with honour.