Everyone has bad days. But for some souls fate comes down hard and fast and delivers a load of bad luck so rotten that the events of that person’s life from that point on have to be filed into two categories: before the bad day and after.

Around dinnertime on a still, muggy June evening, not far from the arched entrance to the Manhattan bridge, bad luck came down like a pile-driver on a spot of ashphalt in the middle of Canal Street. Or more specifically, on a middle-aged, grocery-laden Chinese woman who happened to be crossing that spot of asphalt in the middle of Canal Street.

Anyone who’s wiped out on their bike or witnessed a fight break out in a bar knows that you don’t so much see the event as much as the jumbled memory of the event is just suddenly present in your brain. Whatever you were thinking or talking about is instantly and mysteriously replaced by a madly repeating image loop of that quick, violent moment.

On this particular day I was walking with a friend to a favorite Chinatown restaurant, and as we rounded the corner of Bowery onto Canal, our conversation ceased. Before us a terrific, heartstopping scene was unfolding: In front of me and to my left, where the roadway angles up to the bridge approach, a big, dust-coated cement truck rolls to a stop, its breaks moaning and jerking. I pan right, and my eyes settle on a crumpled figure, surrounded by spilled bags of food, in the middle of the crosswalk. Her right arm is raised, like she’s waving to someone on the sidewalk, and she starts to use her left elbow to prop herself up, and for a second I think she’s going to dust herself off, gather her groceries, and walk away. But then she lies down, slowly, like she’s about to take a nap.

And then I see it: Accumulating underneath her legs is an actual, bonafide pool of blood. At this point the light changes and the cement truck, which has come to rest exactly where a cement truck isn’t supposed to stop during rush hour on Canal Street, still isn’t moving. As a chorus of car horns fills the air up and down Bowery, the driver of the truck, a young guy, tan and as dust-covered as his vehicle, steps down from the cab, takes a few steps, looks to his left and pauses. This is when I witness my second crumpling figure of the day. He stumbles backward and collapses on the steel runner of the truck cab and buries his head in his hands.

But before I can process Phase One of the event, before I can apprehend the unretouched pathos of a middle-aged Chinese lady getting hit — no, getting run over, actually ker-thump-ker-thump run over — by a cement truck, Phase Two is already under way. Out of nowhere appear no fewer than three New York City cops, two plainclothes (but wearing “NYPD”-emblazoned T shirts and cool beltloop-holstered pistols) and one uniform. I mean, these guys just materialize.

Plainclothes No. 1 is already kneeling down by the Chinese lady, cradling her head in one hand while talking calmly into a walkie-talkie held in the other. Plainclothes No. 2 is already taking a statement from the truck driver, and the uniformed cop, perhaps the biggest hero of the three, has single-handedly immobilized four lanes of southbound Bowery traffic.

The sight of the cop holding a bleeding Chinese woman’s head in his lap in the midst of the furious noise and fumes of Canal Street is almost too much to bear, but what really gets to me, what really lodges a stone in my throat as I stand there watching, are the groceries. The grapefruit that’s rolled into a nearby pothole, the bundle of scallions at the cop’s feet, the spilled rice — all these little indices of what the Chinese lady was going to be doing that night, the next morning, the night after, if she had crossed the street a few seconds earlier.

By the time EMS arrives, I’m ready to get out of there, but my friend is still transfixed, and we stick around long enough to watch the paramedics expertly hook up an IV, lift the woman onto a stretcher, and load her into the ambulance.

Though neither of us has much of an appetite, my friend and I force down a few spring rolls and, after dinner, walk over to the arcade on Mott Street and play our favorite video game, one called Crazy Cabbie or something, where you slam your car into guard rails and retaining walls at high speeds and send pedestrians bolting for cover.

On my way home, I pass by Canal and Bowery again and everything’s gone: the truck, the spilled groceries, even the blood. A river of people moves across the spot where the Chinese lady lay earlier. I look around for the plainclothes cops, thinking perhaps they stake out this corner regularly, ready to leap to the rescue at any moment. But there’s nothing but cars, civilians, and the sleepless industry of Chinatown.