Impossible!
There was, however, the whole matrix of mental gadgets, hypnotic beams, educators and other gewgaws of the alien culture. The old thought patterns could easily be erased and replaced by a new system. That would—despite theological arguments to the contrary—result in a new person. For all beings are what their experiences and their training makes them.
A sentience produced in a humanoid body on a remote planet and mentally hurled into a human brain will change the human to an alien in thought and deed—but capable of living as a human! There is nothing in thought that is inimical as there would be in the sheer complexity of biochemistry.
Thoughts, even nasty vagrant thoughts, do not kill. But how large is the lethal dose of polio virus or potassium cyanide or unmatched blood?
An autopsy they might some day perform, but unless they could read her thoughts, they would find nothing! How then to identify the alien?
Nay! How then to prove that there were aliens!
There were both excitement and suspicion when Carroll built the teleport in his asylum laboratory. It was too much like incarcerating a man who had the ability to walk out of the place without half-trying. In fact, as one of the guards put it, that's exactly what it was.
It was Majors who smiled and shook his head. He pointed out that so far there were but two of them, one in the office of the psychologist Pollard and the other in the Wisconsin home of the inmate himself. Both were turned off.
Majors, not really understanding the principle of the things, had them both placed in a sealed room. Whether Carroll could turn on an inert machine from a remote place he did not know and he was taking no chances.