How does John le Carre use imagery in The Spy Who Came in from the Cold?

Imagery:

"Pushing up the collar of his jacket, Leamas stepped outside into the icy October wind. He remembered the crowd then. It was something you forgot inside the hut, this group of puzzled faces. The people changed but the expressions remained the same. It was like the helpless crowd that gathers around a traffic accident, no one knowing how it happened, whether you should move the body. Smoke or dust rose between the beams of the arc lamps, a constant shifting pall between the margins of light."

"It is said that men condemned to death are subject to sudden moments of elation; as if, like moths in the fire, their destruction were coincidental with attainment. Following directly upon his decision, Leamas was aware of a comparable sensation; relief, short-lived but consoling, sustained him for a time. It was followed by fear and hunger."