When I heard the sound, I thought it was a stack of dishes crashing on to the cafe floor. Turning, I expected to see a flipped tray. What I saw instead was empty chairs and bodies crouched beneath tables. People had their hands interlaced across their bent heads, as though bracing for a plane’s rough landing.

It was the summer of 2022. I was on holiday in Stockholm with my friends and former college roommates Allie and Sherry. The afternoon was wet and bleak, with blasts of wind that blew the rain sideways. We had finished touring the Royal Palace and were in search of sustenance. Sherry found a nearby cafe and we ran down puddled sidewalks with our jackets held over our heads.

I remember thinking what a relief it was to be inside, where the warmth calmed my goose-pimpled arms and the air smelled like cardamom buns. We had just begun to divide our slab of lox on rye when the violent crack of what sounded like a gunshot silenced the ambient chatter of two dozen cafe-goers. In my memory, no one screamed.

A few years earlier, I had been working in the US as an English teacher. I remembered the laminated piece of paper that listed our emergency protocols. For an active shooter, you were supposed to evacuate. If you couldn’t flee, you found a safe place to hide. “There is always a staff bathroom.” This was my mantra as we snatched Allie from her spot at the counter, where she had been looking at the pastry cabinet, and moved to the cafe’s back area.

Employees squatted beside a human-sized mixer, beneath a steel prep table, behind a row of unpacked boxes. We rounded a corner and found a narrow door with a brass knob. Another customer was hiding nearby, crouched against a row of lockers. We pulled her into the bathroom with us and twisted the lock.

I don’t remember explicitly fearing death. Instead, I felt a sense of the world narrowing, like at the end of a cartoon where the scene shrinks into a circle as black overtakes the screen. My pulse beat against the corner of my jaw like a panicked bird.

How long between hearing the noise and opening the bathroom door? It couldn’t have been more than five minutes. Maybe only three. But fear stretches time. When we finally heard a giggling voice announcing that everything was fine, it felt as if hours had elapsed. Another voice, in case we hadn’t believed the first: “Really, you can come out now.”

Perhaps not the most convincing line if you are speaking to people who believe themselves to be the target of an at-large shooter, but we opened the door all the same. Two staff members stood there, laughing with relief. They explained that an intense gust of wind had broken a window, shattering the glass with such force that it sounded as if a bullet had burst through the pane. It was nothing, they told us. There had never been a threat.

“Ha ha,” I said. “Funny.” Afterwards, we walked to the bus stop. It was still raining and the sky was the colour of dishwater. In the bathroom, we had briefly discussed whom we would call, should it come to that. Allie was the only one whose mobile phone had data. We agreed she would call her mother in Texas. “Don’t forget to call your mom,” Sherry told her as we made our way to the bus stop. We were going vintage shopping; someone wanted a sweater. “Why?” Allie asked. “Nothing happened.” “Oh,” Sherry said after a moment. “I guess you’re right.”

But I understood why Sherry had reminded Allie to call. It felt as if our family should know we were safe, even though we always had been. It felt important that our loved ones knew we loved them.

People often credit near-death experiences (real or perceived) with giving them a heightened sense of their own mortality. But what those few minutes gave me was a renewed appreciation for the people who were already in that bathroom with me. How glad I was to see the three of us when I glanced in the mirror above the rusted sink. I didn’t want to think about being alone, like the woman we had pulled from the lockers. Somehow, she had been separated from her friends.

It’s impossible to predict who will influence your life when they enter it. Allie was my freshman-year roommate; Sherry and I were in the same orientation group. We have known each other for more than a decade. Each year, we take a trip together. There was a particularly memorable expedition to Bruges where a pigeon crapped on Allie’s shoulder and an angry concierge chased us out of her luxury hotel’s lobby.

The three of us have set off the fire alarm in our college dorm room (we tried to make doughnuts), huddled in the backseat of a tow truck (I drove our rental car over a rock), raced through the Louvre (it was closing in less than an hour), cried in a Portuguese bar (why did none of us live in the same city?), shared a steaming cone of perfect Belgian fries (after cleaning Allie up following the pigeon incident).

The love of friendship is rarely described with the grandness of romantic love. But it is no small thing. Actually, it is everything. I realised in that bathroom. It is the congealing macaroni and cheese eaten together at 3am; it is the apology for saying something that didn’t sound cruel in the moment; it is the hot hiccups of laughter over the stupidest joke ever told. It is knowing, with the kind of certainty that is all too rare, that you will not be left behind. It is staring at a door you are not sure you will walk through alive, knowing that you have been held and changed and seen.

Women and Children First by Alina Grabowski is out now (The Indigo Press, £12.99). To support the Guardian and the Observer, order your copy at guardianbookshop.com. Delivery charges may apply