Enzo was sitting outside his balcony with his usual cigarette and a bottle of whisky to get through the night.
He kept thinking about the incident that happened between him and Cain earlier at the office.
Although he will never admit that to himself, Enzo has been scared that Cain will soon out shadow him, and the only way to avoid that scenario is to eliminate him, it was better he take actions now than when he it wi get worster.
Cain knows too much about him to let go of him just like that.
What if he decides to sell him out to the police or something, as much as he is a bit distracted from his revenge he didn't need more of that distraction.
Cain has a lot of evidence of his illegal transactions, and also people that he has murdered so far including Reporter Kim.
So he would never risk letting him stay alive because Cain can actually change his mind at any time.