Your intervention gives the Desi you suspect is real just enough time to gain the advantage. While you had been pulling your punches, Desi has no such qualms. He shoves his firearm in his imposter's stomach and pulls the trigger. The other Desi collapses, lifeless, to the floor. Blood pools from his bullet wound and soaks his body crimson. Desi spits on the corpse of the mimic. "Púdrete en el infierno," he mutters under his breath. Then he clasps your shoulder and gives you a grin. "Thanks. I really owe you one." From what you can tell, his mannerisms seem perfectly natural. You breathe a sigh of relief.