Watch for an amusing display of "musical extras": as the action takes place at the casino tables, with Tony Blake and his alcoholic gambling lady-friend in the forefront, the same extras can be seen rhythmically passing over and over again behind them, seemingly never stopping to gamble their chips. After a while of impassively passing, they recognize one another, and facetiously start greeting each other, thus providing dynamic entertainment to The Magician's background.
Tony pulls up to a building saying "Rental Office" after he visits the rental office. He is actually going to Diane's apartment, having obtained her address from the rental office. The Rental Office sign is featured later, meaning that the film crew never removed the sign or that there is a rental office in the same building as Diane's residential apartment building.
The EMTs take the wounded Max to his hotel suite on a gurney for no apparent reason, and then take him to the hospital.
During the rental car scene where Tony Blake (Bill Bixby) is doing the long stem rose illusion a string could be seen coming from the vase.
Diane recognizes the hit man as "the man she rented the car for". But earlier it was established that she never saw who rented the car for, and Owens handled all the arrangements.