Perimeter Threshold Check

I navigated from beneath the low table across the open floor toward the main entrance. The floorboards ended at a raised brass threshold separating the interior from the tiled entry. I knelt beside the door frame. A dense rubber seal ran along the bottom edge of the heavy door, blocking outside airflow. I placed the recovered glass marble against the brass seam to test the floor leveling. It rolled two inches left before settling into a shallow depression near the jamb. Floor incline noted. Muffled footsteps echoed briefly from the hallway outside, then faded. The boundary remains secure.