Roma knows that Lingk will try to cancel the sale from the moment he sees him approaching the building. Roma does everything he can to avoid talking to Lingk, because he has already gotten what he wants from him—a signature on a contract&mdashand now anything Lingk has to say can only be harmful. Roma is amazingly adept at improvising his story about "D. Ray Morton". Levene does not share Roma's speed or agility at lying, and stumbles whenever Roma gives him a chance to perform as "Morton." This contrast between Roma's and Levene's improvisational skills marks another clear demonstration of Roma's superiority as a salesman.
Lingk is not a stupid man—he seems to be wise to most of Roma's tricks—but he is very weak. He wants to please Roma, and would very likely choose to fall victim to Roma's trick here, were it not for his desire to please his wife, who has sent him on this errand. The tension of the situation is nearly overpowering for Lingk; he acts as if he is on the verge of tears, stuck in the dilemma of disappointing either Roma or his wife.
Roma understands Lingk's psychology, and knows that this sale—and therefore his own new Cadillac—depend on Lingk choosing to listen to Roma rather than Mrs. Lingk. This is an extremely delicate and tense situation, as Mamet makes us wonder if Roma, the master salesman, can succeed in this scam. The tension rises as, simultaneously, Baylen starts yelling for Levene—who, as "Morton," pretends not to hear—and Aaronow emerges angrily from interrogation. The multiple voices and motivations give the office a circus-like atmosphere.
Still, it seems that Roma might manage to salvage his sale. When Lingk tells Roma that his wife has insisted he call the Attorney General if he cannot cancel the deal, Roma brushes it off: "No, no. That's just something she 'said.' We don't have to do that." We have seen characters make "saying" and "talking" go from meaningful to meaningless, and vice versa, several times in the play, so it seems that Roma has a good chance of making Lingk think his wife's words are unimportant. Roma's subsequent speech—about certain things that married couples must do together and other things that one must decide individually—represents an attempt to empower Lingk as he did the previous day.
By including this very obvious example of a scam in the play, Mamet emphasizes the fact that all the characters are trying to scam each other at all times. The Lingk encounter provides a microcosm of how the entire sales industry—and arguably all American business—works.