How does Nat Hentoff use imagery in The Day They Came to Arrest the Book?

Imagery:

"Mr. Moore was wondering whether anyone in the social studies department had a large photograph of Martin Luther King, but he dropped the idea. It would look phony - the only photograph on the wall without himself in it. Maybe he could say he'd been sick that day. No, too curious a coincidence. Well, he must invite more black speakers. There was certainly an imbalance on that wall. It would take a while to make it ten percent black, but that was a sound goal." (Narrator, Chapter 4, page 23.)

"Actually, my Grandfather had a twist to that. He once told me, "When someone plunges into the sea and drowns, you can't blame the sea. You must learn to swim." That's what I'm doing all the time. Swimming and thinking, thinking and swimming right along." (Kate Stevens, Chapter 16, page 169.)