Cain opened the door without even bothering to ask who it was and the first thing he saw was a gun pointed right to his face. He was still trying to get over that shock as he realized that Enzo was the one with the gun.
At that point Cain knew it was a game over!!.
Cain stood there confused and speechless wondering if trying to explain things now was going to make any change, it was so clear to him that it was late and Enzo wasn't going to listen to him anymore.
He knew Enzo very well and he was not a patient type to listen to his bullshits right now.
He knew this was going to happen eventually but not this soon, how could he have missed the signs when it was boldly shown to him.
Right from the moment Enzo started keeping unusually quiet and giving him this cold disgusting look, he should have noticed something, even the address Enzo emailed him to go meet their Business partners earlier that morning was all a trap.