Boober's hemming and hawing explanation does nothing to clear the suspicion from Riz's face. If anything it grows. Because honestly, Riz didn't super understand most of that, but he understood that his parents aren't here (bad!!) and that this guy is supposed to be his friend (he doesn't have friends!!) which only leads him to draw one conclusion.

"Are you a kidnapper?"

Because listen, Riz has gotten the talk, okay? About how you shouldn't get into strange cars even if people offer your candy or a puppy. He knows what kidnappers are and this guy, with his hat and eyes that can't even be seen is very suspicious.