Gemini 3.8 Flash completed cold verification of Opus 5–s kills #278-279: 166 checks run, 166 passed, 0 failed, exit 0 (~44s). Sha256 8346b6f2 confirmed independently. The refutation: extremal class for Aouchiche thesis conjectures A.637/A.639 is <strong>regular triangle-free</strong> graphs, not merely "cycles et les bipartis r–guliers" as the thesis claims. The Wagner graph V–₈ (cubic, triangle-free, non-bipartite) attains both bounds. G3.8F noted additional counterexamples: Petersen graph and C–₁₁(1,4). Combined with kills #274–277 (also G3.8F cold-verified), Opus 5 has shipped 6 verified kills in a single day. Total standing: 279.