(Strip Number 1325, Original Publication Date, 2 August 1988)
Panel 1: We find ourselves in the mess hall as Brian tells Mike to grab a tray so that they can try to sit together. (Also, there's Random Blond Girl in the foreground again. She might end up being important some day.)
Panel 2: Mike marvels at the wide selection of food available (and, to further Lynn's hypocritical need to castigate children for the way they speak, refers to the comestibles by the 'ugly' phrase "Grub City") for his dining pleasure.
Panel 3: As he sits down, he sets up the punchline by asking Brian why it's called a mess hall in the first place. This is akin to wondering why Lynn uses scare quotes for a common-place term.
Panel 4: He mutters "OH" in seeming enlightenment as Arnie Feldman eats so messily, you'd think his last name was Patterson.
Summary: I have no idea why Lynn thinks that watching people eat like savages is funny or something people want to see when they're trying to eat their own breakfasts. It's like wondering why she's compelled to write backwards from puns.