How does Eric Ambler use imagery in A Coffin for Dimitrios?

Examples of Imagery:

"His face was smooth and oval and pale and he had very brown, anxious eyes that made you think of a doctor's eyes when he is doing something to you that hurts. He frightened me."

Macbeth would probably have hesitated at the last minute to kill a criminal Duncan just as much as he hesitated to kill the Duncan whose virtues pleaded like angels.