The clock begins again

An original narrative about an invented clock-repair workshop.

The clock lay open on the workbench, its hands fixed at twenty past three. Around it, Arun had arranged the tools in a careful row. He checked their order, moved the smallest screwdriver a little to the left, then checked them again.

His instructor stood on the other side of the bench. She did not offer advice. Beneath the bright lamp, the loose cog looked no larger than a shirt button. Arun reached towards it with the tweezers, but his hand stopped before touching it. He drew a slow breath and bent closer.

On his first attempt, the cog slipped and vanished beneath the edge of the clock. Arun's chair scraped backwards. For a moment, he stared at the empty space. Then he lowered the lamp, chose a finer pair of tweezers and found the cog caught against a spring. This time, he rested his wrist on the bench before lifting it. He fitted the cog into place without looking towards his instructor.

Arun turned the key. One tick sounded, followed by another. The second hand moved steadily around the face. He watched it complete a full circle, then placed the clock upright and returned the tools to their case.

"It is ready," he said, before his instructor had asked.

How does the writer show Arun becoming more confident while he repairs the clock?