Irony < Steely ?... I'm hilarious

After reading Once Upon a Time by Nadine Gordimer, I was shocked by the gruesome ending of the story.  However, I couldn't help but notice that there was a lot of situational irony caused by this ending.  I noticed many different sources of this irony.  First was Gordimer's presentation of the story as a children's story.  It uses simple diction and syntax as well as a simple and seemingly happy/ideal setting.   This clashes with the bloody conclusion of the story.  Another level was the caused by the means of the boy's death.  The "DRAGON TEETH" metal coils were meant to protect the family and the house.  However, the coils only effect is to kill the boy.  They never prevented any intruders from entering the house.  This irony is drawn further by the last line of the poem.  "And they carried it [the bleeding mass of the boy]- the man, the wife, the hysterical trusted housemaid, and the weeping gardener - into the house (p236)."  The same people who supported the defenses are injured by their installation, and to finish the novel, they carry the boy into the one place they felt was unsafe, their home.  All of this irony seems to serve a dual purpose in the short story.  Primarily, the irony makes evident the foolishness and childishness of the characters' precautions.  Also, it shows how nobody can run from misfortune.  Disaster strikes everyone, and can come in unforeseen ways.   Nobody can live a perfect life.