Roll a corrected latent forward. Each step multiplies yesterday's error by κ and adds fresh noise: eₖ ≤ κᵏ·e₀ + supδ/(1−κ). Plain version: if κ<1, every old mistake fades geometrically and the new noise can only pile into a finite puddle of height sup‖δ‖/(1−κ) — the rollout is trustworthy. If κ≥1, errors feed on themselves and avalanche to infinity — "correct-then-roll" is meaningless. Contraction isn't decoration; it's the licence to roll out in latent space at all.