Again it’s a prison lingo. That’s why the lunch lady didn’t understand him. I believe I’ve never heard it either (you might ask what kind of Russian I am to not know so many Russian words, but as I said it’s феня – not exactly the Russian that people talk daily. Some start talking it under certain conditions but even than not always) but it’s not that hard to guess, I guess.
Шутить, шутка, шутя, шутняк – something you can do effortlessly, шутя, not a big deal.
His runaway fellow translates it for the woman as тревожно, making her think it’s an army combat term, which she readily does, the word corresponding to the battered looks of both the fake Chechen war veterans.
-Лучше и то, и другое We’d rather have both (the chicken and the goulash she’s willing to cook them)