Revealing mistake: When Hawkeye and Margaret turn toward the stove, and he says "Are you hungry?", watch the can. Though it is meant to look like it blew the top off, it is plain that the top was just set into the top, and a blast of air was used to blow it open. This is because of the sound, and a stream of vapor that often accompanies a blast from an air gun. A sealed can set on a heat source would have burst not only from the top, but also from the side at a seam, or the bottom. Also, they were about five feet away from the can, and the beans went up, not out at a ninety degree angle. So they wouldn't get beaned. Beans on the face were for comic effect.
Goodbye, Farewell, and Amen - S11-E16
Other mistake: How did Hawkeye Pierce, a surgeon, know how to drive a tank? It is nothing like driving a car and takes skills, training and experience that a surgeon simply would not have. He wouldn't even be able to start the engine.
Frank Burns: You disgust me!
Hawkeye: You're right, Frank... I discussed you with everyone I know and we all find you disgusting.
More trivia for M*A*S*H
Question: Talking with stripper Candy Doyle, Potter remarks that he still remembers how she used to spin her tassels and that he is reminded of this every time he sees a C 42 revving up. On the net I do find references to a C40A, a C47 and others, but no reference to an aircraft of the time called a C 42. What would he have been referring to?





Answer: The C-42 was a military variant of the Douglas DC-2. Very few C-42's were built, so it's questionable that Potter would specifically have seen that particular model, but, given his military background, it's not entirely unreasonable that he might use the military designation even when the aircraft in question is actually a civilian DC-2.
Tailkinker ★