The Vitamin G-Man (1943)

A detective in training is about to take his final exam. He is sent to room 13, where his professor befuddles him with a tricky doorknob. Next, he goes to a tea party with his professor loosely disguised as an old lady; the butler serves a pot of "T.N.Tea" even though his back is full of knives. The professor keeps disappearing; the student tracks him by his footprints, even though the footprint powder at one point becomes train tracks and the doors he opens have a skeleton and some card-playing ghosts. Finally, the budding detective phones for the police; when they arrive (driving on the phone lines) and pile into the phone booth, he passes, and is given the first, second and (under bright lights) third degree.

Unfortunately the movie The Vitamin G-Man is not yet available on HBO Max.