Mike Farrell adjusted his headphones, leaned into the podcast microphone, and smiled.

The host had just asked an unexpected question about his time playing B.J. Hunnicutt.

He didn’t ask about the emotional weight of the series finale, or the political messaging of the scripts.

Instead, he asked how the cast managed to survive filming the incredibly heavy, blood-soaked operating room scenes without losing their minds.

Mike let out a long, knowing laugh.

He explained that those scenes were, without a doubt, the most miserable part of the job.

Stage 9 at the 20th Century Fox lot was basically a massive warehouse.

It was freezing in the early morning, but by the afternoon, the massive studio lights turned the soundstage into an absolute sauna.

To make the surgical scenes look authentic to the medical profession, the prop department didn’t use plastic.

They used actual animal organs and cuts of meat sourced from a local butcher.

After eight hours under the blazing hot production lights, the smell in the room was horrific.

The days were grueling, the medical jargon was difficult to memorize, and the emotional tone of the scenes was always incredibly heavy.

But the cast had one saving grace.

Because they were filming in a surgical setting, they were required to wear medical masks.

The audience, and the cameras, could only see their eyes.

Mike explained that the regulars quickly realized they could get away with absolute murder behind those masks.

When the camera was focused tightly on a guest star, Mike and Alan Alda would silently cross their eyes or mouth ridiculous things to try and break the other actor’s concentration.

But one sweltering afternoon, making faces simply wasn’t enough.

Larry Linville, who played the notoriously pompous Major Frank Burns, was in the middle of delivering a massive, self-righteous monologue.

Larry was a classically trained, brilliant actor, and the absolute sweetest man in real life.

Which made messing with him completely irresistible.

The camera was locked tightly on Larry’s face as he dramatically yelled at the nurses.

Mike and Alan were standing right beside him, just out of the camera’s frame from the waist down.

The scene was incredibly tense, quiet, and serious.

And that is exactly when they decided to strike.

While Larry was passionately delivering his medical dialogue, staring straight ahead at the surgical table, Mike slowly shifted his weight.

He gave Alan a subtle nudge with his elbow.

Alan glanced down toward the floor.

Very carefully, operating entirely under the sightline of the rolling camera, the two actors slowly reached down.

Frank Burns was screaming at the top of his lungs about military regulations and patriotism.

Meanwhile, his two co-stars were quietly unlacing his heavy army boots.

Larry was an absolute professional.

He felt them moving around his feet, but he didn’t flinch, break eye contact, or drop a single line of dialogue.

He was completely locked into the performance.

Mike took the left boot lace.

Alan took the right boot lace.

Working together in total silence, they tied Larry Linville’s boots together in a tight, reinforced double knot.

Then, they slowly stood back up, tucked their hands neatly into their surgical gowns, and waited.

Larry nailed the monologue perfectly.

It was a brilliant, flawless take.

The script called for Frank to deliver one final, biting insult to Hawkeye, dramatically spin around on his heel, and storm out of the operating room in a massive huff.

Larry delivered the final insult with absolute perfection.

He spun on his heel with theatrical flair.

He went to take a massive, aggressive step forward toward the door.

But his feet didn’t move.

With his ankles firmly bound together, Larry pitched forward like a felled tree.

His body remained completely rigid as he crashed face-first into a metal tray of prop surgical instruments.

The deafening clatter of metal bowls and scalpels echoed across the silent soundstage.

There was a split second of pure, stunned silence in the room.

Then, absolute chaos erupted.

Alan Alda immediately collapsed over the surgical table, wheezing and clutching his stomach.

Mike Farrell had to lean against a wooden tent pole just to keep himself from falling over.

The director, who had been watching the scene on a small monitor and couldn’t see the floor, leaped out of his chair in an absolute panic.

He was terrified that his actor had just suffered a sudden medical emergency.

But when the panicked crew rushed over to the surgical trays, they found Larry Linville face-down on the linoleum floor.

His shoulders were shaking violently.

He wasn’t hurt at all.

He was laughing so incredibly hard that no sound was coming out of his mouth.

He rolled over onto his back, held up his tightly knotted boots for the crew to see, and yelled a string of hilarious profanities at Mike and Alan.

The heavy camera rig was visibly shaking on its pedestal because the operators were laughing too hard to hold it steady.

After a few minutes, the director finally managed to calm the room down.

They untied Larry, reset the surgical trays, and called for action to shoot the scene again.

But the joke had completely broken the room.

Every time Larry started his serious, dramatic monologue, he would unconsciously glance down at his feet to make sure they were still separated.

Alan would notice Larry looking down, which made Alan start laughing behind his surgical mask.

Mike would hear Alan laughing, which immediately made Mike break character.

Within three seconds of the director calling action, the entire cast was in tears all over again.

Multiple retakes failed spectacularly.

They eventually had to completely abandon filming and take a twenty-minute break outside just to let everyone get the giggles out of their system.

To this day, Mike admitted on the podcast, it was the hardest he ever laughed on a television set.

The prank was so successful that it became a running joke among the crew.

For the rest of the season, whenever an actor had a long, serious monologue in the OR, they would constantly shuffle their feet between lines just to make sure they hadn’t been tied together.

Millions of viewers watching the show at home thought they were experiencing a tense, dramatic medical drama.

They had absolutely no idea that just beneath the bottom edge of the television screen, the most respected actors in Hollywood were acting like bored kids in a high school study hall.

It was the only way they could survive the heavy, depressing reality of the stories they were telling.

They had to create their own joy in the room, even if it meant ruining a perfectly good take.

Humor is often the best defense mechanism we have against the darker parts of life.

Have you ever tried to hold in a laugh during a completely serious moment?