The watchman’s round

An original fiction passage set in the nineteenth century.

The watchman paused at the warehouse door. A light shone through the upper window, although every clerk had gone home. He put down his lantern and pressed his ear against the wood. Inside, a chair scraped across the floor. He tried the handle, then took a small whistle from his pocket. Before he blew it, he looked towards the lane, checking whether the constable was still within sight.

Give two actions the watchman takes to investigate what is happening inside the warehouse.