*What was that a nice way of saying? Beat the shit out of any kid caught so much as jay-walking? Yes, he'd been that way himself in his time, and it was a nasty little cul-de-sac, every bit as bad as being sentimental." The fact is, we may lose Tetherdowne altogether," she said, "which would be a shame. I know it doesn't look like much . . ."
"- but it's home," he laughed. The joke fell among thieves. She didn't even seem to hear it.*
I would like to ask a native speaker about the phrase "to fall a joke among the thieves". I was not able to find the meaning on the internet. I thought that it could be an idiom. From the context, I would say that it means the joke did not cause any response and that it was ignored but I am not sure.