Supplement V expands the mechanical architecture introduced in earlier volumes by formalizing the physics of boundaries, Spotlight radius, and displacement reactions. This document defines how internal visibility, sensitivity, and illumination parameters generate predictable boundary behaviors under symbolic load. The supplement clarifies three core contributions: (1) a mechanical model of boundary contraction, expansion, and collapse; (2) the operational geometry of the Spotlight as a safety-radius device regulating relational distance; (3) how displacement emerges as a deterministic overflow behavior when symbolic pressure exceeds local capacity. This volume situates boundary mechanics within the broader Δ→Projection→Shadow→Pressure framework established in Volumes I–IV. The result is a unified treatment of how humans regulate proximity, threat, and withdrawal through internal physical parameters rather than psychological interpretation.