Loop-Induced Stellar Runaway: Back-Pressure Suppression of the Supernova Bounce and Direct Black Hole Formation in Eigenfield Loop Zones

We identify a previously unrecognised stellar death pathway arising from the eigenfield loop energy accumulation mechanism in supermassive black hole binary environments. A massive star situated within the null geodesic loop zone of an active SMBH binary receives a continuous inward radiation pressure from the loop energy reservoir — the same reservoir derived in the companion paper. For quasar-luminosity sources, this back-pressure is sufficient to suppress the supernova shockwave at the stellar surface, preventing envelope ejection. The result is a runaway compression feedback structurally identical to a planetary runaway greenhouse effect: higher core temperature drives greater luminosity, drives greater loop return, drives greater compression, with no natural termination within standard stellar physics. The iron core cannot explode. It compresses through photodisintegration and neutronisation without the pressure relief of a bounce, collapsing directly to a black hole with no detectable supernova — a dark collapse. The mechanism additionally produces an anisotropic radiation pressure force along the dominant eigenfield eigenvector that modifies the SMBH binary orbital trajectory, offering a new contribution to the final parsec problem. Three previously unrelated observational puzzles — anomalous dark collapse events, the final parsec stalling of SMBH binaries, and the statistical overabundance of black holes relative to neutron stars in dense galactic nuclei — are connected under this single mechanism. Nine falsifiable predictions are derived, testable against existing transient surveys, binary AGN catalogues, and gravitational wave sky localisation data.