Geological disposal safety assessments distinguish normal evolution from inadvertent human intrusion. Normal evolution is treated as the expected long-term behaviour of the disposal system; human intrusion is treated as a stylised future human action whose probability cannot be forecast reliably over geological timescales. This distinction is justified, but it can obscure a protection-relevant question: which pathway is more likely to produce a meaningful dose over a specified assessment period? This paper proposes comparing both pathways through P(D ≥ D*), the probability that a pathway produces a dose equal to or greater than a specified meaningful-dose threshold. The central claim is architectural: normal-evolution compliance, cumulative boundary-bypass probability, conditional consequence after physical intersection, and likelihood of meaningful dose are distinct quantities that should not be collapsed into a single plausibility judgement. The Finnish TURVA-2012 review illustrates the issue: human intrusion was the only disturbance scenario producing dose within the 10,000-year window. Normal evolution is the most fully modelled pathway, but the repository’s engineered and geochemical barriers are designed to suppress corresponding exposure. Human intrusion is less predictable, but once waste or contaminated material is physically intersected, it may be more exposure-efficient because it can bypass the attenuation sequence on which normal-evolution safety depends. A safety case may therefore be complete as a compliance demonstration while remaining incomplete as a protection claim. This note addresses that architectural gap by reframing human intrusion and normal evolution as competing pathways to meaningful dose.