As a Great Gatsby lover, I know every inch of this and can tell you they stop at Wilson's garage on the way to New York City.
They would be put into room to be sorted between “healthy and able to work” and “undesirable for work”. Those who were healthy and able, would be taken to another room to possibly shower and get their uniforms. Those who were undesired would be taken to gas chambers or would get shot.
The figurative language is personification
At the end of the second one it is personification