How does McMurdo (Mr. Douglass) manage to impress McGinty in their first meeting. Example from the novel to support the answer.

McMurdo impresses McGinty with his demeanor.... he shows no fear.

“True for you, Mr. McMurdo. Why did you leave Chicago?”
“I’m damned if I tell you that!”
McGinty opened his eyes. He was not used to being answered in such fashion, and it amused him.
“Why won’t you tell me?”