Source A: Thirty-seven minutes underground

The job sheet called it a routine inspection. At 6.10 on Tuesday morning, that description seemed accurate. Four of us stood beneath the riverside park, checking bolts and recording measurements in a flood-control tunnel that had been dry for weeks. Above us, commuters were beginning to cross the bridge. Down there, the city was reduced to concrete, electric light and the patient hum of machinery.

Mara, our supervisor, moved ahead with a torch tucked under one arm. She had completed the inspection so often that she could identify each chamber by its echo. At the first gate, she tapped the metal twice and listened. At the second, she pointed out a rust mark no wider than a pencil line. Nothing in her voice suggested urgency. We followed her in the obedient rhythm of people doing a familiar job.

At 6.18, I noticed that the air had changed.

It was not colder, exactly. It felt occupied. A faint vibration travelled through the soles of my boots, and somewhere beyond the wall came a sound like furniture being dragged across a distant room. I looked at Mara. She was no longer examining the gate.

“Back to the shaft,” she said.

Nobody asked why. The absence of explanation was more alarming than a warning would have been.

We had covered perhaps half the distance when the first water appeared. It did not arrive as the dramatic wave I had imagined in safety exercises. A thin grey line slid around the bend and spread across the floor, almost politely. Then it thickened. Within seconds it had become a shoulder pushing into the tunnel, carrying leaves, foam and a plastic bottle that spun upright as if trying to see where it was going.

At 6.22, the control-room operator called through the radio. Heavy rain had fallen several kilometres upstream. Sensors showed that water was entering the system faster than expected. His voice remained measured, but behind it I could hear other voices, clipped and overlapping. Someone was closing road barriers. Someone else was contacting the fire and rescue service. The emergency shaft was being opened from the surface.

We began to run.

Our boots struck the walkway out of time. The tunnel that had seemed broad on the way in narrowed around us. Every handrail became an obstacle; every pool concealed the floor. Ravi slipped at the final gate and hit his knee. He tried to stand, failed, and laughed once — a small, shocked sound that belonged in another place. Mara and I pulled him between us while the water worried at our ankles.

The radio called again. Two minutes had passed.

By the time we reached the shaft, the water was above our boots. The ladder rose through a black cylinder towards a square of daylight no larger than a postage stamp. A rescue officer shouted down, but the shaft broke his words into fragments. A line descended. A second followed. Above us, unseen hands tightened ropes, counted rungs and repeated our names.

Ravi went first. Then Mara. I waited with the fourth member of our team as the water climbed from ankle to shin. I remember staring at the red needle on a wall gauge, although I no longer understood what it measured. The equipment around us continued to blink and hum, perfectly composed.

At 6.47, I reached the surface. The quiet park had become a working site of engines, lamps, barriers and people in bright protective clothing. Traffic had stopped on both sides of the river. An ambulance crew examined Ravi while engineers watched readings from the control room. Thirty-seven minutes after we entered the tunnel, all four of us were out.

Later, an investigator explained that the rain had missed the park entirely. From the bridge, the morning had looked harmless. The water that reached us had begun its journey beyond the visible sky.

My copy of the job sheet was returned in a clear plastic sleeve. Across the top, beside the date and our four names, were the words “routine inspection”. The paper was dry. The word was not.