What effect does the reputation of the description of rainforest lifting the door knocker and it's cracking and then booming sounds have on the reader

This scene brings up a lot of gothic elements in the story. General Zaroff's mansion is large, elaborate, and gothic (think Dracula) looking. The large gargoyle knocker adds to the sense of mystery and ominous feeling about the scene. The size of the knocker and large thud it makes gives the sense that Rainsford is entering a large and potentially dangerous place.