How does William Armstrong respond when the narrator pokes his head through the post of the bed to look at him?

In the story "The Last Leaf" by O. Henry, when the narrator pokes his head through the post of the bed to look at William Armstrong (commonly known as "Old Behrman"), he responds with surprise and a mix of irritation. Behrman is initially taken aback and questions the narrator's actions, but he also shows a protective and caring side, reflecting his deeper concern for the narrator's well-being and the situation at hand. This moment underscores Behrman's character as a gruff yet compassionate figure.