I stare into the dark tunnel and find myself imagining how it would look to Isaac.

To an eight-month-old, the shadowed subway opening wouldn’t seem ominous but a grand curiosity. Shards of reflected light frame its entrance like shiny pieces of broken glass. Would Isaac try to touch them? Would he finger a droplet of misty water rolling down the jagged wall and put it on his tongue?

The cavern wouldn’t frighten my son. It would excite him with possibility and mystery.

A horn blares and I flinch. The night’s last express approaches. I’m without company on the below-ground platform but I am joined by a wicked aroma. It’s coming from a green, paint-chipped metal trash can that I’m guessing from the scent contains the carcass of an extremely dead sandwich. The trash can sits along the wall, beneath a dimly-lit poster advertising a service that promises to turn your mobile phone into a day-trading terminal. “Buy Low, Sell High, Commute Profitably.”

Isaac would love little more than exploring the contours of the iPhone with his mouth.

I turn back to the track and squint across the platform. I’m looking for the woman with the triathlete’s calves. I saw her upstairs at the turnstile, a brunette with darkly-tinted skin wearing a skirt and a look of compassion. A burly beggar approached her and she gave him some money and a kindly, worried smile.

How come all the beautiful women who look like they were born to heal the damaged are going a different direction than me on the train?

Would she be a great mom?

Would she be impressed that tomorrow I become this year’s recipient of a national magazine award for investigative reporting? Would she help me feel impressed?

A rumbling roars from the tunnel. It’s not yet my train, the K, but the nearing Express, expressing.

Over the din, I hear rustling from behind me, something heavy hits the pavement. A boot step, then another. I turn to see a mountainous man in a leather jacket materialize from the darkness, stumbling towards me. He’s the picture of a San Francisco drunk, downtrodden but wearing a fashionable coat with collar upturned, curly beard, and dark shades. Bum doubtless with a blackberry, and a limp.

I’m tempted to ask him if he’s okay as the train whooshes out of the tunnel into the station.

The drunkard lunges, or trips. He careens toward me, leading with his arms as if pushing through a revolving door.

He’s going to fall into me and then both of us onto the tracks.

Powerful palms crash against my chest, fingers claw my sweatshirt, his jacket slick with January rain. I begin to fall backwards, not two feet from the edge. I grab his beefy forearms to try to break the hold at his vulnerable wrist joints, or steer us sideways. I fail. I stumble backwards. The train’s warning horn explodes: move or die!

I feel it pass too close behind me, air-brushing my scalp.

Isaac. My son. Will I see him again?

One last tactic.

I give in. I try to pull the drunk on top of me. Our momentum abruptly changes. We fall not backwards into the train, but straight down to the pavement. My coccyx slams onto my backpack, which in turn smashes into the ground. My spine unfolds, neck extending toward the concrete. I brace for impact.

Crack. I see an instant of light, then one of black, then a hazy return to the moment. I smell something like burning tires. Then cologne. I feel intense pressure on my chest.

The mountain man lies on top of me. But I’m alive. The base of my skull must have hit the edge of the cement but just after the train passed, sparing my life.

I frantically push and kick the mountain from atop me. I claw the cement, then roll over, panting in downward dog. I run a triage check. Limbs moving, no obvious fractures. I feel sticky warmth at the back of my skull, a cut but not deep and shy of the heavy capillary-bed on top of my head that would bleed profusely and require stitches. I attended med school a decade ago before quitting the profession to become a journalist, but I remain fluent in the vernacular and anatomy of survival.

I look up to see the drunk. He’s ambling awkwardly, his gait a demi-sprint. He holds his arms close to his chest. He disappears into a darkened stairwell. From his pocket, something falls, a piece of paper, onto the damp cement.

“Don’t move. You might be hurt,” says a voice from my right.

It’s the brunette, the one from the turnstile. Where did she come from? My vision remains unfocused.

I blink hard and look for words.

“Breathe,” she says. She kneels and extends an arm and puts fingers on my shoulder. She’s shaken too.

Her touch brings attention to the acute pain near my deltoid. The strap of my ratty black backpack must’ve given me a nifty friction burn. But it also probably spared me a rougher fall. The pack, which follows me everywhere, contains an overflow of magazines and notes, the flora and fauna from which journalism sprouts and, tonight, a serendipitous back pillow.

I exhale, emerging from shock. I’m out of acute danger. Overcome with intense relief.

I run back a reel of the last minute. I picture the man coming at me, falling but somehow purposeful, his face camouflaged.

“Say something,” the brunette encourages. “Did you know that guy?”

“Scleroderma,” I mutter.

“What?”

I don’t express my thought: the drunk’s skin was pulled tight against his forehead and around his eyes. Scleroderma means “tight skin.” Its presence can indicate a rare disease of the organs, very rare, so these days it is much more likely to indicate a visit to the dermatologist; this drunk recently had an injection of botox that tightened his wrinkles. Rich drunk.

My scrutiny is a sign of my own condition: excessive medical analysis. Some people focus on faces, or names. I remember pathologies. My not-very-exciting sixth sense is seeing illnesses and physical conditions, a vestige of my medical school training. Jaundice, clinical water-retention, lazy eye, gout, misaligned spine, all the herpes variants, emphysema cough, flat-footedness (the obsessive medical labeler can identify it even when the flat-foot is wearing shoes and walking by). Even though I’d abdicated a career in medicine for one in medical journalism—after realizing I lacked the intensity and rigidity to be a good doctor—I can’t shake associating humans with their conditions.

“It doesn’t feel right,” I say.

“What? Your head?” The brunette asks.

“That too.”

I stand, feeling her fingers fall away. I wobble, get my footing, walk unsteadily to the piece of paper that fell from the mountain’s leather jacket. I pick it up.

It is lined and legal sized, creased and smudged with black grease. I unfold it and discover two names written in blue pen. One name is Sandy Vello. Doesn’t sound familiar. The other name does.

“What is it?” the brunette asks.

I point to my name on the piece of paper. She shakes her head, uncertain what I’m talking about.

“This is my name?”

“What?”

“Nathaniel Idle.”

“I’m Faith,” she says, still not getting it: My name was on a piece of paper that fell from the pocket of a man who nearly turned me into subway smoothie.

“That wasn’t an accident,” I say.

“Do you think you need an ambulance? I suspect you’re in shock.”

I look at Faith. She’s biting her lip with perfect teeth, her head tilted, concerned, compassionate, empathic. My eyes lock on her for a millisecond more than is appropriate. I am struck by an urge to make her laugh. But it’s overwhelmed by a more powerful compulsion.

I look at the stairs where the dangerous mountain disappeared. I sprint after him.