Then there came the sound of many feet tramping and dying away in some passage which sent up a clanging echo. I turned to run down again towards the vault, where I might find the new entrance; but at the moment there seemed to come a violent puff of wind, and the door to the winding stair blew to with a shock that set the dust from the lintels flying. When I ran to push it open, I found that it was hopelessly fast. I was again a prisoner, and the net of doom was closing round me more closely.