As he describes one of Stevie’s only acts of public rebellion, Conrad employs foreshadowing and auditory imagery to illustrate both the chaos of the scene and the future repercussions of the young man's actions:
He touched off in quick succession a set of fierce rockets, angry Catherine wheels, loudly exploding squibs – and the matter might have turned out very serious. An awful panic spread through the whole building. Wild-eyed, choking clerks stampeded through the passages full of smoke; silk hats and elderly businessmen could be seen rolling independently down the stairs.
The auditory imagery of Stevie’s youthful defiance paints a vivid scene of chaos for the reader. Conrad’s descriptions of "fierce rockets," "loudly exploding squibs," and "angry Catherine wheels" create a strong and vibrant soundscape. Each of these auditory images carries a sense of urgency and unpredictability, echoing the chaos and panic that Stevie's actions cause.
Stevie has essentially been tricked into starting the fireworks by boys who torment him. The fireworks aren’t meant to hurt anybody, but nevertheless their loud sounds and choking smoke cause a “stampede.” The sounds aren't just loud; they're aggressive and violent. As they echo through the building they cause distress, making “elderly businessmen” roll down the stairs and lose their hats. The words "fierce" and "angry" as the narrator uses them here suggest not just the noise but the emotional effect of the fireworks on those affected by them. This group of sounds—listed one after another in quick succession—makes the reader feel as if they are in the midst of the chaos, hearing every explosion and witnessing the panic.
Beyond the scope of this scene, the link between Winnie’s brother and destructive, public explosions hints at future events. It subtly suggests that this act could be a precursor to more significant acts of terrorism involving Stevie. Verloc is quick to exploit the lingering association between explosions and the cognitively impaired young man, as the reader soon finds out.