Get Out of My Body!

Consider an alien infiltrating our world—impossible to catch because he might inhabit any person—even you! You'd likely start screaming—
I have come to discuss a very grave problem, said the talking-attendant.
Then let's get down to details, said Chester Forge. It's urgent you said.
Interviews with Ravians always made Chester nervous. They wouldn't use the psi-control voice sets, and there was something uncanny in talking to a human, a talking-attendant, when you knew it wasn't the man speaking at all, but the alien intelligence he was temporarily host to.
It was even more unsettling when the Ravian was a high official, as at present. Their minds were even more coldly intellectual, dry and logical than the usual Ravian tourist's. And they could make a lot of trouble. Chester's job as tour-chief here at Knoxville—more specifically, Port Knoxville, where the ships came in—was to keep the tourists happy as possible. No, not happy. Happiness is an emotion. Satisfied maybe.
There are scant useful details I can give you, said Monnn, the Ravian, through the lips of the talking-attendant. There was a stowaway on the sightseeing ship that came in this morning—one of our people. He is a fugitive. He has left the ship and is here on earth somewhere, perhaps in Knoxville. He must be captured.
Chester Forge was jolted, but he had found you got on better with Ravians if you never showed feelings. He made his voice calm.
A fugitive, hmmm? What was his crime?
The question is immaterial, said Monnn. So typical of your people. But I suppose you will function better if not bothered by curiosity. Minnn, the stowaway, told a lie.
A lie?
The worst of crimes. Minnn was a politician, campaigning for office, and he lied in making a promise he could not execute.
By Joe, thought Chester, now I've heard them all. Well, the rule is you never, never question the tastes of an alien. The Martians have a mad passion for hop-toads, the Zarlos like to have things hurt them, the Frin talk all the time and the Rorn don't talk at all, and—