At dinner, Ben and Jill watch a "stereo tank"—a television-like device. Douglas appears on the screen delivering a speech and then interviewing the Man from Mars. Smith answers Douglas' questions articulately and uncontroversially. Ben is upset after the interview, thinking that Douglas has enlisted Smith to say whatever Douglas chooses.
Jill tells Ben that the man on the screen is not the same Smith she met at the hospital. Ben does not believe Jill at first, but she convinces him. Ben realizes that, so long as Smith has a false public face, the Douglas administration can kill, or do whatever they want, with the real Smith. Ben decides he needs to get the real Smith out of the hospital.
At the hospital, Jill is told that Smith has been moved to another room. An unconscious old woman now occupies his old room.
Ben brings a man named James Cavendish on his mission to see Smith, whose profession, called "Fair Witness," is to act as a neutral observer in any situation and keep an unbiased mental account of what he observes. Ben also brings a lawyer to the hospital, and they demand to see Smith. Gilbert Berquist, an executive assistant to Douglas, comes to stonewall Ben, but when Ben tells Berquist that he has heard rumors that the Smith interview was faked, Berquist arranges for Ben and company to see Smith.
In his hospital room, Ben comes up with a question that flummoxes Smith, suggesting that he is not the authentic Smith but indeed an actor. Ben and his companions are thrown out of the room. Leaving the hospital, Cavendish suggests to Ben that he should have checked to see if the "Smith" they saw had calluses consistent with Earth gravity and footwear. Cavendish could not have suggested this while in the room, because a Fair Witness cannot interfere while on duty. Ben is frustrated at having missed this opportunity to prove Smith is being impersonated. Headed home, Ben's automated flying cab stops obeying his orders and takes him to a courtyard where he finds himself losing consciousness.
As part of her nursing duties, Jill needs to retrieve a powered bed, and recalling one in Smith's old room, she heads there. The doctor on duty watching the old woman on a video screen ask Jill to hold his post for a moment while he runs to the bathroom. Jill decides to enter the unconscious woman's room and retrieve the bed. Inside the room she sees Smith and realizes that the woman is only there so that no one will suspect that the real Smith is also there.
Remembering their previous "water-sharing," Smith is delighted to see Jill. She tells him not to tell anyone that he has seen her and leaves. Later, she returns and gives Smith nurse's clothes in which to disguise himself. They sneak out of the hospital. In the cab together they have an awkward conversation, wherein Smith tries to communicate Martian concepts that translate imperfectly. Realizing that people will look for her now, Jill decides to route the cab to Ben's apartment.
Jill encourages Smith to wiggle his toes in the carpet of real grass in Ben's living room. Smith hesitates to walk on a living thing, but he senses that it is the grasses' proper purpose to be walked upon. Jill draws a bath for Smith, who, believing water to be sacred, is stunned at the notion of submerging his whole body within it. He delights in the experience, and, curious, tries to grab at Jill's breast as she bathes him.
Berquist breaks into the apartment with a police officer. Jill jumps at the officer, who slaps her. Frightened by this treatment of his "water-brother," Smith instinctively reaches toward the officer and makes him disappear. Berquist pulls out a gun. Smith "groks" (a Martian word roughly equivalent to "understands") that Berquist intends harm, and Smith makes Berquist disappear as well. Jill screams. Fearing he has done wrong, Smith goes into a contemplative trance. Jill cannot rouse him, but knows that they must leave immediately, so she packs him into a large bag and leaves the apartment with him.
These chapters progress in a fairly typical adventure story manner, stacking the odds against our heroes and building suspense. Ben knows that the Douglas administration may have reason to kill Smith and their use of an actor to portray Smith implies that they may very well be planning to kill the real man, but Ben has no proof for his theories, and only he and Jill seem to know the truth. Although we do not see Douglas's true motives or intentions, the actions of the police imply that Ben's most paranoid fears are correct: they kidnap Ben and try to kidnap Smith and Jill as well. With Ben missing, it does not seem as if there is anything Jill will be able to do to protect Smith from the overwhelming power of the police.
The novel is filled with offhanded references to various artifacts of future technology and culture. There are flying automated cars, the "Federation" that governs Earth, and Chapter VII introduces one of the most idiosyncratic concepts of Heinlein's future society, the "Fair Witness." The concept of a person legally recognized to be impartial in all situations would seem almost more in line with an imagined past than an imagined future, as it involves no technology more complicated than the ceremonial robe the Fair Witness wears. The oddity of this creative legal fantasy within the science fiction narrative is a testament to the breadth of Heinlein's vision. His ideas about a future society are not limited to speculating at scientific advances.
Although previous chapters have explained preciously little about the Martian race or their society, we begin to see glimpses of Valentine Michael Smith's mentality in these chapters. We see in his conversation with Jill that many of his Martian concepts do not maintain their meaning when translated into the English language and Earthling custom. On Mars, water is rare and water-sharing a rite of deep understanding between individuals, but Jill thinks nothing of sharing a glass of water with Smith. Water is no more sacred to her than taking a bath, another notion that is utterly foreign to Smith. However, implicitly trusting Jill because of their water-brotherhood, Smith consistently takes pleasure in the things that she instructs him to do.
For the most part, the discussion of Martian custom and philosophy is limited to vague similes and intimations of the incompatibility between Martian thought and Earthling. Heinlein, however, lays the groundwork for the exploration of one significant Martian concept with the introduction of the Martian word "grok." This is the only Martian word, a verb, which appears in the novel. "Grok" begins to appear, without explanation, in descriptions of Smith's thought processes, and though we may first be confused by it, Heinlein uses it often enough that we may start to comprehend it in context. At its most basic level, we can see that to grok something means to understand it deeply. By giving us a word that is alien but makes sense in context, Heinlein helps to simulate a Martian mindset for us.
Chapter VIII concludes with a shocking display of Smith's powers that throws a wild card element into the equation of suspense. We have seen before that Smith has abilities that Earthbound human beings do not, such as willfully slowing his bodily processes to a stand-still. Furthermore, it is implied that he has some psychic abilities, such as when he "senses" from the leaves of grass that is their purpose is to be walked upon. But when he makes Berquist and the police officer literally disappear, Smith demonstrates that he has what could be considered super powers. The ability to psychically make one's enemies disappear would seem to make Smith a much more formidable individual than anyone could have known. Because we do not understand Smith's powers, and Smith's motivations are undefined, we cannot know how these powers will come into play in the struggle to come.