She swallows, because otherwise she'll be too nauseated to talk.

"How can they enforce that? Don't people try to get away?"

(She remembers a short story they had to read in English class last year, about a village and a black spot and a woman screaming It isn't fair and the matter-of-fact way the other villagers stoned her to death. She remembers sitting there feeling cold as her classmates talked casually about death happening at random and man's inhumanity to man.)