Therefore, as 20x20m room is approximately 400 square meters and allowing for some overlap: one search turn (10 minutes) to carefully search 400m2 of floor space. Each of the twelve towers in the Iron Mountain Ark is roughly 2600 m2 (per floor, times 18-20 floors) (times 10 levels). So, approximately 65 minutes to carefully search a floor, Again, rounding in the favor of the players, about an hour per floor. Which is admittedly what I started at.