Duvall stepped up to him quickly, and spoke in a pleasant voice.
"I'm mighty sorry," he said. "I rang your bell by mistake. Pardon me."
The man glared at him, suspicion blazing from his eyes.
"That's an old one," he retorted. "How do I know you ain't a burglar?"
"Do I look like one?" Duvall asked.
The man ignored this question.
"Rang my bell by mistake, did you? Who do you want to see?"
"I have some business with a lady on the fourth floor." He went closer to the man, and lowered his voice. "I'm a detective, my friend," he whispered confidentially. "I'm here on a very important case."
The big man's eyes widened.
"Th' hell you are!" he exclaimed. "Central office?"