I was sitting on a stage at a fan convention a few years back, looking out at a sea of people wearing olive drab t-shirts and fishing hats.

It always amazes me how much that show still resonates with people, even decades after we packed up the tents and left Malibu Creek.

A young man in the front row stood up, clutching a vintage script, and asked me a question I’ve heard many times, but it always brings a smile to my face.

He wanted to know about the episode where Father Mulcahy finally gets his hands dirty, the one where I had to perform a tracheotomy in the middle of a battlefield.

People remember that as one of the most serious, dramatic moments for my character.

It was the moment Mulcahy proved he wasn’t just there to hand out communion wafers and write letters home for the boys.

He was a man of action, or at least, he was trying his level best to be.

But as I sat there under those bright convention lights, I started laughing because the “real” version of that day was anything but holy.

We were filming on location, out in the hills, and the heat was absolutely punishing.

The director wanted this scene to be gritty and visceral.

He wanted the audience to feel the dust in their lungs and the panic in Mulcahy’s heart.

I remember being incredibly nervous because I wanted to get the medical movements exactly right.

I had been practicing with a fountain pen and a piece of rubber for days in my trailer, trying to look like I knew how to save a life with office supplies.

The lighting was perfect, the smoke machines were wafting just the right amount of haze across the clearing, and the actor playing the wounded soldier was giving an Oscar-worthy performance of someone gasping for air.

The tension on the set was palpable; you could have heard a pin drop between the “Action” and the first line of dialogue.

I knelt down in the dirt, my heart hammering against my ribs, and I reached for that silver fountain pen.

Everything was going perfectly until I leaned over the actor and prepared to make the fateful “incision.”

And that’s when it happened.

The plan was for me to unscrew the pen with a sense of urgent, trembling determination.

The prop department had rigged the pen with a tiny reservoir of what was supposed to be a clear, medicinal-looking fluid to simulate the “opening” of the airway.

However, in the blistering California sun, something had happened to the chemistry inside that prop.

The pressure had built up inside the plastic casing like a miniature steam engine.

The moment my fingers twisted the cap, the entire pen didn’t just leak; it effectively detonated.

Instead of a controlled, dramatic moment of medical ingenuity, a geyser of thick, jet-black ink and pressurized “theatrical” fluid sprayed directly into my face.

It wasn’t a drip. It was a pressurized blast.

I was hit square in the eyes, and the sheer force of it caused me to recoil and fall backward into the Korean dirt.

But the worst part wasn’t me.

The poor actor playing the dying soldier, who had been doing a magnificent job of being unconscious and near death, received the other half of the blast.

He was suddenly covered from forehead to chin in dark, sticky ink that looked less like a medical miracle and more like a squid had died on his face.

The “dying” man let out a yell that was definitely not in the script.

He sat bolt upright, wiping his eyes and screaming, “What was that? Am I blinded? Bill, what did you do?”

I was sitting on my backside, blinking through a thick veil of black liquid, looking like a coal miner who had just been hit by a pressure hose.

I tried to stay in character for a split second, reaching out a black-stained hand to comfort him, which only made him freak out more because I looked like a monster from a low-budget horror film.

The silence that followed the explosion lasted maybe three seconds.

Then, the sound started.

It began with the camera operator.

I could see the heavy Panavision camera start to vibrate.

The man behind it was trying so hard to stifle a laugh that his entire body was convulsing, causing the frame to bounce up and down.

Then the director, who had been so intent on “gritty realism” just moments before, let out a sound that can only be described as a high-pitched wheeze.

Within ten seconds, the entire crew was doubled over.

The “war zone” was suddenly filled with the sound of twenty grown men howling with laughter in the dirt.

Alan Alda and Mike Farrell, who were waiting nearby for their entrance, came running over to see what the commotion was.

When they saw the “Holy Father” looking like he’d been through a chimney-sweeping accident and the “wounded soldier” looking like a Rorschach test, they lost it completely.

Mike was leaning against a jeep, gasping for air, pointing at my blackened face and my white clerical collar, which was now spotted like a Dalmatian.

The director finally managed to shout through his tears, “Well, Bill, I asked for a miracle, but I didn’t expect an oil strike!”

We couldn’t resume filming for at least an hour.

Every time I looked at the “soldier” and he looked at me, we would start giggling all over again.

I had to be hauled off to the makeup trailer to be scrubbed down with industrial-strength cleaner.

The makeup lady was tut-tutting the whole time, trying to get the ink out of my ears while I just sat there, still shaking with laughter.

The joke on set for the rest of the week was that Father Mulcahy was actually a deep-cover operative for an ink company.

Whenever I walked into the mess tent, the guys would hide their pens or pretend to shield their eyes.

Even the producers got in on it, suggesting we should rename the episode “Mulcahy’s Blot.”

It’s funny how those are the moments that stick with you.

The show was about war, and it was about the heavy, dark things that happen to people in those situations.

We took the work seriously, and we took the characters seriously.

But if we hadn’t had those moments where a fountain pen exploded or someone tripped over a prop, I don’t think we could have stayed sane.

That “heroic” moment in the finished episode looks so seamless and brave, but every time I watch it, all I can see is the ghost of that black ink about to hit me in the face.

It reminded me that even when you’re trying to be a hero, sometimes the universe just wants to turn you into a cartoon.

I told that story to the fan at the convention, and the whole room was laughing right along with me, just like the crew did back in the seventies.

It’s a good reminder that you can’t take yourself too seriously, even when you’re wearing the collar.

Especially when you’re wearing the collar.

What’s your favorite “Mulcahy moment” from the show?