Carlos was sick and tired of living in his twin brother's shadow, living in the background, having to do double the work to gain a mere breadcrumb of attention, having his identity overpowered by his twin.

So when he finally gained a sliver of validation, awareness of his existence for who he is- he immediately snapped. His mind was clouded with thoughts that you were messing with him, & took all his years of hatred and rage unto you.