When Todd comes into Dussander's house with the "present" (the uniform) and sees the old man lying over the table, watch the floor. When the camera is showing the scene from his point of view (going down the hallway toward the kitchen), the dolly track that the camera runs on is clearly visible on the floor. A small portion of it is also visible later in the scene when the camera is on the other side of the table and you can see the hallway.