The smell in the air were rather dull, sterile in fact. Nothing smelled musty or old, as if the interior was perfectly maintained. There was no coating of dust covering any of the treasure. As for the routes, the same metallic smell of gold and silver seemed to flow from all of the paths except for the stairwell down. Smells of fresh water seemed to draft up from the depths. It's possible the other routes only led to more of a livable fortune laden castle. 

Upon closer inspection of the spiral staircase, it seemed that there were crumbles of stone all around it, as well as coating the steps themselves. It was the same stone as the floor was made out of. It looked as if the entire staircase had been hidden under the floor before, but was freshly uprooted by something. The dust of the rock being smashed was still lingering in the air.