Under the ridge

An original fictional scene set in an old tunnel beneath a ridge.

The entrance was little more than a split in the hillside. Ferns leaned across it, their wet leaves brushing my shoulders as I stepped inside. Behind me, the afternoon remained bright and ordinary. Ahead, the tunnel swallowed the path after only a few metres.

I switched on my torch. Its beam found a row of iron hooks in the wall, each one furred with rust. Water tapped somewhere beyond the light, slowly and evenly, as if it were counting my steps. When I stopped, the tapping continued.

At first, I could walk upright. Then the roof lowered and the walls pressed closer together. My coat scraped against the stone whenever I turned. I told myself that the pale marks beside my head had been left by tools, although some looked too fresh. A thread of cold air touched the back of my neck and disappeared.

The notebook I had come to collect lay beside an abandoned lantern. As I bent to pick it up, a stone clicked behind me. Another answered farther down the tunnel. I swung the torch round, but the beam showed only the empty path and a faint cloud of dust settling across it.

I began walking back. The entrance should have been visible beyond the bend, yet the darkness seemed to have moved nearer. This time, when my footsteps echoed, one of them arrived late.

How does the writer make the tunnel seem threatening to the narrator?