How does Agatha Christie use imagery in Murder on the Orient Express?

Imagery:

All around us are people of all classes, of all nationalities, of all ages. For three days these people, these strangers to one another, are brought together. They sleep and eat under one roof, they cannot get away from each other. At the end of three days they part, they go their several ways, never, perhaps, to see each other again."

"...if you wish to catch a rabbit you put a ferret into the hole, and if the rabbit is there he runs. That is all I have done.'"