Eric, having been uncovered, had to think fast. He could run, but then Umi would figure he was a bug and just kill him, so he decided to walk straight up to him. He walks up and starts shouting at the top of his lungs the most obvious thing that came to mind: "UMI! I'M NOT A BUG!!!" hoping this would at least convince Umi that he wasn't a bug. Or at least a very WEIRD bug.