I scan a coworker’s bookshelves, my back to the revelry of guests I don’t know well, and never will. Ninety minutes is enough time spent steeped in the loneliness of this Mission District Christmas party. I drain my second margarita, bid the host goodbye and dash to Church and 16th to catch the last MUNI train of the night.

I’m alone in the railcar except for the fluorescent-lit passenger across from me, a duffel bag at his side. He’s maybe 19 or 20, a few years younger than I am. If I were to report him I’d say he was tall and lanky, with short-cropped hair, new sneakers, a scarlet varsity jacket. He considers me, a slim brunette, through narrowed eyes. I slide my gaze to the windows. Lights and concrete blur behind the reflected oval of my face, my maroon beret. His glare fixes on me. I’m a mole, he’s an owl. My gut clenches like a fist.

I’ve been here three years, since 1990, and know this train, know it’s four minutes until the next stop. In four minutes, I can walk from my apartment and past Polk Street’s young hustlers to buy beer at Big Apple Grocery. They never bother me. I’m not their type.

The man leans over, unzips his bag, and yanks out an assault rifle that looks carved from ebony. Like a weapon used in real war. My eyes dart to my Doc Martens. I see him at vision’s edge, see him lift the gun, see him target my head from five feet. Then, through the roar of blood in my ears, above the hammer of heart in my chest, I hear him cock it.

I love my mother but don’t think of her. Don’t think of her wrapping sandwiches in waxed paper at dawn, or shoveling snow like it was fun, or how she still called me Pumpkin. Flashes of my short life don’t hurtle through my mind: three sisters splashing in a blue plastic pool, the world spinning in cartwheels and backflips, a lover’s arm across my torso as I fade into dreams.

I focus on my lungs’ shallow push and draw, my black leather shoes, the rigid seat against my spine, the train’s rumble as it slows for Market Street. I focus on the man’s movements in the periphery. How he lowers the gun, uncocks it, and tucks it in its bag as if putting an infant to sleep. How he zips the bag and heaves it over his shoulder. How he rises to six feet, slips out the sliding doors, and recedes into the station’s amber light.

My breath comes hard and fast. Three women burst into the car. Lipstick, lace, combat boots. Mirth. Words evaporate before I grasp them. Another stop. Two men join the party. Leather jackets, leather pants, wallet chains. Jumbled laughter in high and low notes. I’m small, invisible. The train slows again. I white-knuckle a steel pole and pull myself up, willing my knees not to buckle.

I gain my balance on the Van Ness platform and climb the stairs to a fog-smothered city. A blurred half-moon hangs in a starless sky. It’s a mile up Polk Street to the flat I share with roommates plucked from The Guardian’s classifieds. I won’t wait alone for the bus. Head up, shoulders back, assertive stride. I pass the O’Farrell Theatre. Its mural’s humpback whales float above San Francisco Bay, as if the building concealed an aquarium, not a strip club. I pass the lit display window at Bob’s Donuts, the smell of grease and yeast billowing through a gaggle of midnight treat-seekers on the sidewalk. I pass The Cinch. The thump of “It’s Raining Men” lingers for two blocks.

Three lost boys slouch in silence against a thrift store’s facade. A streetlamp captures the purple lesions that mark a familiar boy’s face, a slender boy in Keds and a faded jeans jacket. He’ll vanish from Polk Street by spring, a few months before I move on. The boy stares at me with columbine-blue eyes but doesn’t see me. Sometimes I want to say hello and ask his name. I don’t tonight. I never will.