Impulse

Stuart is Jennifer's boyfriend who notices odd town behavior and becomes a cautious, determined observer. He investigates the milk facility leak and the toxic vault, trying to understand the contagion and protect Jennifer. As danger escalates, he fights to help others, but he is ultimately killed during the confrontation with the involved agent.

Jennifer is the film's central figure who fights to survive as the town descends into violence. She attempts to escape the infected area, witnesses the community's horrors, and eventually takes action to end threats around her. Her resolve keeps her moving toward safety even as the odds stack against her.

Jennifer's brother, a volatile figure who harbors disturbing tendencies toward his sister and becomes entangled in the town's violence. His darker impulses contribute to the breakdown of family bonds and the community's moral compass.

Jennifer's friend who becomes a link to the town's troubled inner world. She provides clues about the town's hidden injuries and helps the central characters understand the danger surrounding them.

The local physician who makes a grim decision to euthanize Margaret (Jennifer's hospitalized mother) and then takes his own life. His actions reflect the moral despair and chaos enveloping the town's institutions.

Jennifer's mother figure, depicted in the housing of illness and dependence within the town's medical sphere. Her presence underscores the personal stakes of the town's collapse.

A government-connected figure associated with the plan to spray the town. His presence, radios, and vehicle link him to the external operations driving the town’s downfall.

The town sheriff trying to maintain order as chaos erupts. He embodies the thinning line between authority and failure under extraordinary circumstances.

The town deputy who stands as part of the local enforcement structure, contending with confusion and escalating violence as events unfold.