Have you ever experienced a moment — a flash of thought, no more than a nanosecond — that separated having a good time from a disaster?

In third grade, it was an exuberant moment with the PE aide, a high school girl, that went from pulling on her belt loops to breaking them, that led to my first meeting with the principal’s paddle. In college it was that third bottle of $3 wine the night before my first-semester final exams that ultimately ushered in my transfer to the second-tier school I call my alma mater.

Yesterday, Thanksgiving afternoon, it was an innocent little run down the hillside with my daughter in my arms that forced a whole restaurant full of people to gasp collectively, and elicited Trish’s typical response after I do something stupid: “Well, it looks like they at least have brain stem function.”

This was our second consecutive year to spend Thanksgiving dinner at Graves Mountain Lodge in Virginia with my folks, my step-mother’s brother-in-law and three family friends. The lodge is a big old log … lodge … that sits … at the foot of a mountain. The folks there feed turkey and ham and a bunch of sides to about 1,200 people (some of us lucky ones got two pieces of pumpkin pie, even though we didn’t deserve it).

Since the lodge is on a mountain there’s a big hill from its full-length front porch down to the mountain-fed creek about 100 yards below, a drop of about 35 feet or so. Last year Ella and I ran down the hill, hand in hand, killing time before our seating.

This year I suggested we “fly” down the mountain, like we do in our back yard — I pick her up and hold her out in front of me and she stretches out and flaps her arms like she’s a bird.  It’s great fun. In our back yard. Which does not sit on a mountain, and where the slope is relatively faint and runs only five yards from top to bottom.

I distinctly remember getting off to a good start. Ella flapped her arms and I swallowed the hillside with each stride, each stride that seemed to get faster and faster and fall farther and farther — because they were. I know how my little girl likes to go fast, but after several seconds, after we were well on our way toward the creek, I thought — this is THAT moment — I should slow down.

The super-slow-mo picture in my head shows that thought beginning when my left foot lifted off the ground in one stride and ending before the foot hit the ground again. But thinking back, it seems like that moment was pondered over several minutes, as if I had the time to actually deliberate the  great fun I was sharing with my daughter and the potential dangers inherent in running down a steep hill holding 30 pounds stretched out in front of me. It seems that I should have remembered a little physics, something about velocity and mass and gravity. Looking back, which I’ve done a hundred times in the past 33 hours, it seems obvious that I should have chosen to slow down, or maybe even stop.

But I didn’t. “More!” I told myself. “Faster! Ella’s having a great time! I’m having a great time! This is so much FUN!”

I made a conscious decision NOT to do the sensible thing.

I’m 39 years old. I should know better. When men my father’s generation were 39 they’d been through a depression, a world war, the Korean war, the invention of television. Sure, they would later vote Nixon in twice and invent the leisure suit, but at 39 they were sensible.

Not two steps after I chose to keep going I realized I couldn’t stop. And I realized that I wasn’t just running downhill, I was falling down it. Holding my daughter, stretched out before me, her cranium exposed to the mountainside, her little arms and legs flapping, oblivious to the fact that her old man was endangering her life.

Trish later told me that I actually fell backward first. I vaguely remember this. It makes sense. Otherwise I’d surely have broken me neck and Ella’s, because if I’d fallen straight forward I wouldn’t have had time to respond at all.

I  remember going over — it all seems to have happened sooooo slooowwwwlllllyyyy — dropping my head and tucking my right shoulder. I thought to myself, holy shit, I need to bring Ella close to me, because if I don’t she could shoot out of my arms and into that boulder cropping out of the hillside down there.

I pulled Ella in, tucked her like a football with my right arm and held her head with my left just as my knees slammed downhill. Then my head, then my shoulder and finally my ass, for the second time, hit the grass. I tried to make my body and my arms into a rigid cage, like a NASCAR cockpit — this was my conscious thought, although I never watch NASCAR — to protect her, and it worked, until my legs came over my head and I wasn’t strong enough to support the force of my body (F=ma) and, because my arms were totally wrapped around Ella, I felt myself crush her little middle.

I ended sitting upright facing downhill. There was a millisecond of silence. I was fine, I could move. I looked down at Ella. She moved freely. Whew. There was a fleeting rush of adrenaline and a flash of thought: “Cool! That was great! I bet I had great form!” Then she started wailing. Then I thought, “Shit, if I break our kid Trish is going to kill me!”

I quickly checked Ella’s limbs. They were all there, that was a good sign. Nothing seemed to be broken. There was no blood. I wasn’t sure that I hadn’t caused a massive brain hemorrhage, though.

I slowly got up on my knees. I tried calming Ella. I immediately started apologizing profusely. I looked up the hill. There was a group of people standing in a circle, and a lady in the group looked down at me and gasped with horror, as if she’d just witnessed blatant and horrid child abuse. People on the porch stopped rocking, stopped talking together, just stopped, and stared. Mouths were agape. Eyes were wide.

Trish didn’t move. She stood with our friend waiting for our name to be called. She later told me that once it was obvious that our necks hadn’t snapped and we weren’t paralyzed or brain damaged that she felt very confident that I would handle Ella and she would not. In other words, I made the mess, I could clean it up.

But she is a nurse, for crissake. Eventually, with some coaxing, she walked over to the car, where I’d walked with Ella, because I couldn’t think of anything else to do but if I walked up to the porch I was sure I’d be stoned by an angry mob.

Ella cried for several minutes. Then she was fine. In fact, she was better than fine. She seemed to feel sorry for me, and there was this weird chemical bond between us. Here I was, her dopey old man, trying to show her a good time and nearly killer her, but I was remorseful, regretful and willing to make it up to her. She sensed that, like a dog showing pity for its master and licking his hand.

I’ve been trying to remember the last bonehead thing I did that endangered my only offspring’s existence. I’m sure it was recent, but I can only recall the first time she fell off the edge of a bed, where I’d sat her, the first time I watched her alone, when she was 5 months old.

So that was the highlight of Thanksgiving, 2007.

What a trip.