When Binghamton, at McHale's hut, is telling the crew about turning down their request and how he hates himself for doing so, Parker is holding an iron. When the camera angles changes the iron is now laying on the table.
Binghamton refers to Gruber as "seaman" a sleeve rank with 3 slanted stripes. He's actually a petty officer 2nd class torpedo man. The Captain was probably joking that Gruber would be busted when he went to the brig.
At the raid when Binghamton say "fancy meeting you here" to McHale, the shadow of the boom mic is visible on the curtain behind them.