After all the talk Arsenio's made of how his country sees monsters, it's interesting seeing here how until now the others haven't ever fully comprehended what he meant by that. And of course he's also facing his old friend who, likely because of their shared religion, probably thinks the only way he can save his friend is to kill him. Would also explain why he wants to do it himself. This is his friend. If he has to die, he wants to be the one who does the deed.