Question about "The Merchant of Korea"

Okay, so I watched this episode the day you posted this, watched as close as I could and I think I found what you're looking for.
This is the episode where B.J. gets a letter from peg saying that the land they've been waiting to buy is finally available but they need a $200 dollar down payment. Hawkeye convinces Charles to loan B.J. the money and Radar goes off to wire it to Peg.
They'be been sitting inside/outside of their tent drinking their hooch and Hawkeye asks Charles to join them in a celebratory drink. He pours a martini and says, "Mother Pierce's Liquid Landmine." Letting Charles know the name of the drink. Now, this is where Both Alda and Farrell speak the same line but Farrell only gets the first half out before he realizes it's not his but Alda's. "You sip it through a fuse."

Farrell says, "You sip it-" and then realizes what he's done and then nods as Hawkeye finishes as if not missing a beat. It's kind of hard to notice but check for that next time this episode airs.