I have travelled so far but on the threshold, right at the turnstiles, I think this: Do I really want to enter a 20 metre deep, 7th century BC Turkish cave city, where you move from one level to the next by crouching down and slithering through tunnels?

Maybe not. Air could be an issue. Anyway, I think I might be claustrophobic. I suspect confined spaces will give me a panic attack. Should I test it here at the Kaymakli Underground City where, single file, we crawl down four storeys?

For thousands of years, people lived (made wine, kept animals, raised children, said mass in early Christian times) in these caves when they were under threat of invasion. When their enemies came, they rolled a giant rock to the entrance of the cave. When my Peregrine guide Süleyman tells me about the giant rock, I feel physically ill.

“We’re not under threat now,” I say. “So maybe I will stay above ground.”

“You will be fine,” says Süleyman. “Follow the blue arrows if you want to get out. You will fit in the tunnels. You won’t get stuck.”

A large group of Japanese tourists surges past us into the cave complex. My heart rate soars. That means less oxygen in the caves for us.

My group move through the turnstiles – and I linger outside, in the air, under the sky, thinking of Brussels.

Ten years ago in Brussels, three friends (two of whom I’d only first met that night) and I were trapped in a very small, old-fashioned elevator. A cupboard really, meant for one or two people. We were trapped for many hours – so many, in fact, that it became my birthday – ticking over to midnight while we screamed for help in three different languages.

Our phones didn’t work and there was no alarm button. We were all pressed extremely close which was fine for the one minute we were planning to be in the lift – but hours? The tops of heads became intimate with armpits. Hipbones nestled into waists. We took turns crouching on the ground to get oxygen. When enough time passed and our cries weren’t heard, a panic set in. The panic was worse than running out of oxygen. The energy of anxiety was trapped and seemed to infect us. Of course we would die in here. And in Brussels. Of all places. In this tiny elevator.

Eventually neighbours heard us and the fire brigade was called. The top was taken off the lift, as neatly as a can of tuna being opened and we were winched out one by one by Belgium firefighters. By then we were wet with sweat despite the winter snow outside. Being pulled out, gasping for air, felt like being born.

Since then I have had two panic attacks, which I recall with near-perfect detail. Silent physiological rhythms become loud. There’s the certainty that a heart attack is minutes away, the sensation of your heart beating too fast and air not getting to the lungs. There’s the animal awareness of exits and escapes.

Why are these experiences of panic so imprinted on the memory when other fleeting sensations cannot be recalled with such vividness?

Is it because you think you actually might die?

Süleyman had been waiting for me. “It will be all right,” he says. I trust him.

So I go in.

The first level is fine. The air is stale, the design Flintonesque, small carved containers lie off a main room where children might have slept and there’s another place for the horses.

“It’s kind of like [Tasmanian art gallery] Mona,” I say to a friend. Also I think, “Follow the blue if you freak out.”

So when Süleyman says the next level is reached via tunnel, and it is maybe 10 metres long or more, I feel scared.

The others – not afflicted by claustrophobia – crouch down and, one by one, frog hop through the tunnel.

I wait at the entrance (thoughts came unbidden of Augustus Gloop, Brant and Todd, the Thai soccer team), unsure if I will proceed. I could just go up and wait in the gift shop.

“Is it OK?” I ask Süleyman.

“It’s fine.”

I crouch and almost run through the tunnel, emerging to another low-ceilinged, dark, stale-aired room. It’s unbelievably bleak. Süleyman shows us a ventilation shaft which looks like a very tall, very narrow well. Looking at it also makes me feel ill. I can imagine being thrown down there in early Christian times for some minor infraction, like stealing cheese.

“I want to leave now, I want to get out of this cave system,” I say as I stick my head into the well and breathe.

By this stage I can’t see any blue arrows, just the dreaded red.

“Just come down one more level and you’ll see the blue arrows out,” Süleyman says.

I hurry down one more level so I could hurry up one more level. I could feel it now, the panic setting in like a fast-growing internal parasite.

I think with horror about the tunnel (would there be another tunnel up?), and the lack of air, and the small anterooms filled with Japanese tourists, and the centuries-old scent of sewage and the 20 metres of rock that sits above us. Are we in an earthquake zone? Could we be buried alive?

On the third level up, my heart – its rate elevated by the climb – starts to thump and I feel short of breath. I sit down on a stone bench in a smaller cave, away from the others. Even though I’m seated, my heart rate isn’t dropping. I struggle for air. This is it. I’m having a panic attack. There’s no air in here. I can’t breathe. I think off the metres and metres of stone above us and the low ceiling and the lack of ventilation and feel crushed. How am I going to get out? Where is the air? Where is the door? No blue arrow. I can’t see any blue arrows!!

There’s no point yelling as I would only waste oxygen. The others are walking, hunched slightly, around this level of the cave but seem in no hurry to leave. They’re casual, as if it were a normal, everyday thing to be in this horrible cave.

I’m sweating a lot now, still sitting on the rock, still breathing fast and shallow, wondering how the paramedics will reach me when I have the heart attack. I have a sedative in my handbag that I was meant to have on the flight from Australia.

I take the pill the way people in movies take pills, trembling hands, a dram of water, almost missing the mouth in the rush to get it in. Valium. Old friend. But then I feel foolish. It won’t kick in for 20 minutes.

By that time I’ll be dead.

Someone asks if I’m all right. I’ve gone very pale, but who can see in this dark cave? Süleyman is there, looking encouraging. I trust him. I see the blue arrow and bolt towards it. I just have to scramble up three more levels, get it over with.

Thirty minutes later at a fancy restaurant, doing a wine tasting overlooking the fairy chimneys of Cappadocia, the sedative will kick in. There is the sensation of floating. And it really is as if I died down there.