Albert Camus uses dilemma to create conflict in "The Guest". Daru is in a lose/lose situation and no matter which way he goes, something horrific will happen.
If he chooses not to take in the prisoner then Balducci would punish him. Initially he refuses to take him in, but with Balducci's orders, he has no other choice because of his authority over him. Balducci, who comes to him in horseback with the convict, is a gendarme and friend of Daru. If he does choose to take him in, the convict's Arab brothers would severely beat him. This is proven later in the short story after Daru leaves the prisoner. "Daru felt a sudden wrath against the man, against all men with their rotten spite, their tireless hates, their blood lust".
Balducci orders him again, and then leaves, and Daru has no choice but to keep the prisoner in the schoolhouse.
That night, Daru cannot sleep because he always hears that there are footsteps outside. The next morning, Daru feeds the prisoner breakfast and they set off toward the prison. Partway there, Daru is faced with another dilemma.
By leading the prisoner to the prison, he would be hated among the other Arabs for turning him in, if he doesn't, then he would be in trouble with the law enforcement of the area. Daru eventually lets the prisoner loose giving him a choice, thus passing a dilemma to the prisoner. If the prisoner leaves towards freedom, he knows that eventually he would either die or get caught by the authorities. But if he chooses to continue on to the prison, he will feel the consequences of committing crime. Knowing these, he continues on to the prison. This does not help Daru though, as no one knows that he let the prisoner...