The reading
The bead. A rage-contagion empties Britain, and the survivors' flight toward safety ends at a sanctuary that turns out to be the real infection — men who have decided the rules are gone.
Engines
- security/safety · content · spine · ~ — the threat (the Infected, the turn in seconds) drives a flight toward a promised military blockade; the spine is the search for a defense that holds. It is found false (the soldiers are the trap) and then seized back by force.
- purity/contamination · content · also-runs · ~ — the Rage virus is a literal contaminant, blood-borne, the clean-vs-infected line organizing every scene. But the film's reversal is the purity-counterfeit's: the soldiers who most confidently sort clean-from-infected — purging the Infected as vermin while planning to rape the women "to repopulate" — are themselves the monstrous thing. Contamination is shown to be moral, not viral.
- impunity · content · also-runs · ~ — the apocalypse-as-license register: with civilization gone, the soldiers' "there are no more rules" is the consequence-removal wish, accountability deleted by catastrophe.
The bundle. The contagion-siege bundle: security chased across a defiled landscape, the clean/infected line drawn and then turned back on the men who drew it most eagerly.
Dual-use read. Same core as the zombie vein: the Infected are the purity-spiral's object (irreversibly defiled, killable without weight), and Boyle — like Romero — names the counterfeit by handing it to the villains. The "purge the irreversibly-contaminated" logic (the Madison Grant register, counterfeit-catalog) is voiced not by the heroes but by the soldiers who use it to license their own atrocity; the film's gratification (survival, the final rescue) is kept separate from that logic.
Verdict. The contagion variety of the vein: purity/contamination as the organizing clean-vs-infected logic, run as critique, with security/safety the bright wish the survivors actually chase.
Evidence. ~ reviewed — from the film (in-copyright). Counterfeit ancestor: counterfeit-catalog (Madison Grant, #68185).