How does Gitta Sereny use imagery in Into That Darkness: An Examination of Conscience?

Imagery:

"Albert Hartl....[while going to dine with a man named Blobel outside of Kiev]...It was evening and just getting dark...We were driving past a long ravine. I noticed strange movements of the earth: clumps of earth rose into the air as if by their own propulsion—and there was smoke... Blobel laughed, made a gesture with his arm...the ravine of Babi Yar...[and said] Here lie my 30,000 Jews...Hartl, a few months after that had, or faked, a nervous breakdown."