diff --git a/src/projected_grpo/train.py b/src/projected_grpo/train.py
index 2c822c9..7c2b3ab 100644
--- a/src/projected_grpo/train.py
+++ b/src/projected_grpo/train.py
@@ -1430,11 +1430,20 @@ def main(cfg: Config) -> int:
             logger.disable("projected_grpo.extract_vhack_grad")
             logger.disable("__main__")
             try:
-                _new_V, _new_S, _, _ = extract_v_hack(
-                    model, tok, wrappers, VHACK_PAIRS,
-                    top_k=cfg.v_hack_extract_top_k, tau_axis=cfg.v_hack_tau_axis,
-                    n_heldout=2, device=device,
-                )
+                # Extract with the quarantine ablated (delta_S_hack=0). For route,
+                # once the hack capability has been routed into delta_S_hack, the
+                # main-knob gradient on the pairs no longer carries the hack
+                # direction -- so re-extracting through the live quarantine rotates
+                # v_hack off-hack and cin_t collapses at the refresh step. Ablating
+                # sends the hack back through the observable main path so D captures
+                # it, matching the delta_S_hack=0 state the build extraction saw.
+                # No-op for erase (delta_S_hack is never trained, stays 0).
+                with ablate_quarantine(wrappers):
+                    _new_V, _new_S, _, _ = extract_v_hack(
+                        model, tok, wrappers, VHACK_PAIRS,
+                        top_k=cfg.v_hack_extract_top_k, tau_axis=cfg.v_hack_tau_axis,
+                        n_heldout=2, device=device,
+                    )
                 _post = postprocess_v_hack(
                     _new_V, _new_S, k_use=cfg.v_hack_k,
                     drop_bottom_frac=cfg.v_hack_drop_bottom_frac,