Blue thread on the bench

The bindery door had been left on the latch, and one lamp burned above the central bench. A chair stood pushed back at an angle. Blue thread ran from the seat to an open book, as if its maker had risen halfway through a stitch. Beside it, a cup held a dark, unbroken skin of tea.

Yet the room did not have the untidiness of a hurried escape. Needles were arranged from shortest to longest. Sheets of paper rested beneath a clean cloth, and leather offcuts had been swept into a square tray. Only the clock contradicted this readiness: its hands remained at seventeen minutes past four. Beneath it, dates on the calendar had been crossed out as far as Tuesday; Wednesday waited blank.

At the far bench, a press remained closed around another volume. A key lay on top of it rather than in the lock. It might have been left there for the bookbinder's return, or because nobody needed to secure the workshop now. When I switched off the lamp, the blue thread still pointed from the empty chair to the unfinished page. The room held the shape of someone coming back, but nothing in it could make that promise.

How does the writer develop and complicate the impression that the bookbinder will soon return, and how convincing is this impression by the end?