While Tom is speaking with Eddie at school (at around 6 mins), Eddie is standing on the stairs above Tom and the camera is behind Eddie pointing down toward Tom when a boy with short brown hair wearing a green and white vertically striped shirt and a dark blue jacket and holding a light blue book walks down the steps past Eddie, turns and stares at Tom, turns and looks up the stairs while rubbing his nose, then looks back at Tom when the camera cuts to a shot looking up at Eddie from behind Tom as the same boy walks down the stairs past Eddie.
Even in 1963 smoking would not have been allowed in a radio studio due to nicotine deposits on electrical contacts, tape heads. etc. nor would food or drink ever be placed on the turntable stands where a slip could knock the arm off the record or dump liquid into the mechanism.
The floor in the hallway runs directly into the open elevator with no gap or threshold.
In the movie's opening scene, while Tom is cooking breakfast, he angrily shuts off the radio by turning the volume/power knob fully clockwise (to the right). That would have turned the volume all the way up! He should have turned it completely counterclockwise.