Why the denial?

Why the denial? 
and this is not a goof because it's straight out trivia that being exposed to lethal radiation for two hours would end up killing her father and her younger brother. A goof would have been if they stayed on their farm  and never felt any . What other reason could there be for denying it?

10 September 2026
#260910-011538-249000Z for Zachariah (28 February 1984)Series: Play for Today (1970-1984)1 item
Trivia Declined (1)

TRIVIA ADDITION

At the beginning Ann's father and her little brother return in their vehicle after looking for the other people in the village. The father tells the story that they saw nobody, rang the church bell, waited for two hours, that they saw dead birds everywhere on the street and finally went into some of the peoples houses and found them dead, obviously from lethal radiation. Even though shortly after the family, and another family, with the exception of Ann drive north in the hope of finding people that are still alive. Since they never came back, it's obvious they all died from the radiation. However, had they stayed, the father and the brother had received enough lethal radiation when they drove out of the village and into the radiation zone where they were exposed to deadly radiation for two hours and they would have died anyway.