Question

The clock on the mantelpiece beat with a heavy, leaden insistence—tick, tick, tick—slicing the afternoon into cold, equal fragments. Clara sat rigid, her fingers laced tightly in her lap, watching the dust motes drift down through the pale bar of sunlight. How slow it was, this waiting, as though the air itself had thickened to amber, trapping her in its clear, suffocating depths. Yet, the moment the doorbell rang—a sharp, brassy intrusion that shattered the silence—the room seemed to tilt and spin. Suddenly, the seconds leaped forward. The maid’s footsteps in the hall were not a sequence of distinct sounds but a rapid, drum-like roll; the door handle turned; the door swung wide; and there he stood, framed in the threshold, his coat damp from the rain, his eyes searching hers. In that single, breathless instant, years of separation collapsed into a dizzying blur of images��the dock at Southampton, the grey swell of the Atlantic, the quiet garden in Sussex—all rushing upon her at once, crowding out the present, until the maid’s voice, asking if she should bring tea, pulled Clara back to the flat, solid surface of the moment, and the mantel clock resumed its slow, indifferent measure.

Which of the following best describes the primary function of the shift in narrative pacing from the slow, deliberate description of waiting to the rapid sequence of events following the doorbell's ring?