1 Prof. Jones: Well this is just terrible! Executed at dawn!
2 Monty: I know, dad.
3 Prof. Jones: {holds up a book} Now I'll never finish the sequel to this mystery novel!

No, I don't know what the heck Sallah is doing back there either. He's not part of this conversation, but I wanted to make sure he was in shot so nobody forgot he was in the cell with the Joneses. So he just sort of ambles around randomly in the background.

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2015-11-02 Rerun commentary: One might presume Sallah is busy looking for a way to escape. That'd be sensible.

There were certainly plenty of good mystery novels around in the 1930s. In fact, this era is part of the so-called Golden Age of Detective Fiction.