diff --git a/src/AcDream.App/Rendering/RetailPViewPassExecutor.WalkLeaf.cs b/src/AcDream.App/Rendering/RetailPViewPassExecutor.WalkLeaf.cs
index e70af5cd..58d8e272 100644
--- a/src/AcDream.App/Rendering/RetailPViewPassExecutor.WalkLeaf.cs
+++ b/src/AcDream.App/Rendering/RetailPViewPassExecutor.WalkLeaf.cs
@@ -18,6 +18,32 @@ internal sealed partial class RetailPViewPassExecutor
     {
         if (!frame.RenderSky)
             return;
+
+        // FW4 slice 6: an INTERIOR root draws the sky ONCE, unclipped —
+        // the same LScape::draw rule as the terrain turn below (view-culled
+        // landscape content is never view-clipped; the clear + seals +
+        // interior repaint own aperture exactness). The former per-slice
+        // scissor left stale sky color wherever the authored exit-portal
+        // bands were narrower than the real opening.
+        if (!frame.RootCell.IsOutdoorNode)
+        {
+            _sky?.RenderSky(
+                frame.Camera,
+                frame.CameraWorldPosition,
+                frame.DayFraction,
+                frame.ActiveDayGroup,
+                frame.SkyKeyframe,
+                frame.EnvironOverrideActive);
+            if (_particles is not null && _particleRenderer is not null)
+            {
+                _particleRenderer.Draw(
+                    frame.Camera,
+                    frame.CameraWorldPosition,
+                    ParticleRenderPass.SkyPreScene);
+            }
+            return;
+        }
+
         ReadOnlySpan<ClipViewSlice> slices = clipAssembly.OutsideViewSlices;
         for (int sliceIndex = 0; sliceIndex < slices.Length; sliceIndex++)
         {
@@ -58,6 +84,31 @@ internal sealed partial class RetailPViewPassExecutor
                 nameof(sliceIndex), sliceIndex,
                 $"walk terrain turn: slice {sliceIndex} of {slices.Length}");
         }
+
+        // FW4 slice 6: an INTERIOR root draws the terrain UNCLIPPED —
+        // retail's LScape::draw draws whole blocks (view-culled, never
+        // view-clipped; "retail never clips ordinary meshes per view"),
+        // and aperture exactness comes from the depth clear + exit seals +
+        // interior repaint that follow in the walk's own order. The former
+        // per-slice scissor+clip under-painted terrain COLOR AND DEPTH
+        // wherever the authored exit-portal polygons are narrower than the
+        // real opening (the #456 cathedral seam bands) — leaving stale
+        // color and empty depth that unclipped alpha (the falls) then
+        // painted straight across. The outdoor root keeps its single
+        // full-screen slice (equivalent to unclipped by construction).
+        if (!frame.RootCell.IsOutdoorNode)
+        {
+            _terrainDiagnostics.Begin();
+            _terrain?.Draw(
+                frame.Camera,
+                frame.Frustum,
+                neverCullLandblockId: frame.PlayerLandblockId,
+                clipPlanes: default,
+                ndcClipAabb: new Vector4(-1f, -1f, 1f, 1f));
+            _terrainDiagnostics.Complete();
+            return;
+        }
+
         ClipViewSlice slice = slices[sliceIndex];
         bool scissor = BeginDoorwayScissor(slice.NdcAabb);
         _surface.BindTerrainClip();
diff --git a/src/AcDream.App/Rendering/Walk/WalkFrameDriver.cs b/src/AcDream.App/Rendering/Walk/WalkFrameDriver.cs
index 588b63f3..ad162c03 100644
--- a/src/AcDream.App/Rendering/Walk/WalkFrameDriver.cs
+++ b/src/AcDream.App/Rendering/Walk/WalkFrameDriver.cs
@@ -744,14 +744,14 @@ internal sealed class WalkFrameDriver : IWalkEventSink
         MarkIfGrown();
         _events.Add(WalkFrameEvent.Sky());
         _skyDrawnThisFrame = true;
-        // FW4 slice 1: the fan count is the WALK'S OWN active view count
-        // (carried on the Landscape event) — retail LScape::draw runs once
-        // per view the walk installed. The old clip apparatus's slice count
-        // no longer participates; the renderer re-derives the actual slice
-        // clip data from the same walk views before replay, so index i here
-        // and OutsideViewSlices[i] there are the same view by construction.
-        for (int slice = 0; slice < activeViewCount; slice++)
-            _events.Add(WalkFrameEvent.TerrainSlice(slice));
+        // FW4 slice 6 (correcting slice 1's per-view fan): retail's
+        // LScape::draw draws the terrain blocks ONCE per landscape turn —
+        // the active views feed only the block-level visibility union
+        // (CheckBlocks); terrain cells are ordinary meshes and retail never
+        // clips those per view (pixel exactness = the depth clear + seals +
+        // interior repaint afterward). One terrain turn, always; the walk's
+        // views still own the punch fans and dynamics apertures.
+        _events.Add(WalkFrameEvent.TerrainSlice(0));
     }
 
     private void HandleDrawCellsTurn(IReadOnlyList<uint> cells)