In Chapter One, "The Hearth and the Salamander," while playing cards at the fire station, Montag observes as though he has not before that the other men are "all mirror images of himself." He reflects upon the old man whose library the firemen burned and asks, "What happened to him?" Betty replies that the man was taken off to the asylum. In disbelief, Montag remarks that the man was not insane.
Beatty arranged his cards quietly. "Any man's insane who thinks he can fool the government and us."
"I've tried to imagine," said Montag, "just how it would feel. I mean, to have firemen burn our houses and our books."
"We haven't any books."
"But if we did have some."
Then, Beatty pointedly asks Montag if he has any books; Montag replies that he does not, but he envision the old man in the park with whom he has spoken.
Montag hesitated. "What--was it always like this? The firehouse, our work? I mean, well, once upon a time..."
These questions are the ones that are significant as they clearly raise Beatty's suspicions. Bradbury signals to the reader that Montag is in dangerous territory as he writes that Montag opens his mouth and
...it was Clarisse McClellan saying "Didn't firemen prevent fires rather than stoke them up and get them going?"
At this point, Stoneman and Black bring out their rule books that contain the history of the Firemen of America and the men all watch Montag. Clearly, their suspicions about Montag's devotion to his job have been raised.