diff --git a/src/AcDream.Core/Physics/PhysicsEngine.cs b/src/AcDream.Core/Physics/PhysicsEngine.cs
index f8eefb4..5414f2a 100644
--- a/src/AcDream.Core/Physics/PhysicsEngine.cs
+++ b/src/AcDream.Core/Physics/PhysicsEngine.cs
@@ -262,46 +262,25 @@ public sealed class PhysicsEngine
             // _landblocks (no DataCache dependency).
             if (DataCache is null) return fallbackCellId;
 
-            // ── Cell-stickiness check (A6.P3 slice 3, 2026-05-22) ──
-            // Before re-resolving via FindCellList, check if the fallback
-            // CellId still validly contains the sphere CENTER (point-in).
-            // If yes, prefer it over any FindCellList result that might
-            // pick a different cell whose BSP also contains the point —
-            // fixes issue #98 (cellar-up stuck at last step due to CellId
-            // ping-ponging between adjacent cells in iteration-order races).
+            // ── Cell-stickiness REVERTED (A6.P3 slice 3 v3, 2026-05-22) ──
+            // Slice 3 v1 (sphere-overlap, 8898166) over-corrected — held
+            // player in cellar even when transitioning out at the ramp top.
+            // Slice 3 v2 (point-in, 3e140cf) closed the ping-pong at the
+            // inn doorway (data confirmed) BUT prevented the player from
+            // reaching the top of the cellar ramp (the stuck spot
+            // transitioned from "ping-pong at top" to "never reach top").
             //
-            // Mechanism: when the sphere is on a cell boundary where the
-            // CENTER is in multiple cells geometrically (overlapping BSPs),
-            // FindCellList's candidate-iteration order (HashSet,
-            // implementation-defined) determines which cell wins. That
-            // order may shift tick-to-tick → ping-pong. Stickiness keeps
-            // the CURRENT cell as long as the sphere center is still
-            // inside it, only switching when the center has moved out.
+            // Reverting to no-stickiness for now. The ping-pong at the inn
+            // doorway returns but is a lesser evil than blocking cellar-up
+            // entirely. Issue #98 cellar-up has a deeper bug that needs
+            // separate investigation (BSP step-physics or AdjustOffset
+            // slope-projection at the cottage main floor boundary).
             //
-            // Uses POINT-IN (not sphere-overlap). Sphere-overlap stickiness
-            // (the first slice 3 attempt) over-corrected — held the player
-            // in the fallback cell even when the center had transitioned to
-            // an adjacent cell, blocking legitimate cell transitions at
-            // stair tops + portal exits. Point-in matches FindCellList's
-            // own semantics for "which cell are you in."
-            //
-            // Retail oracle: cell-array hysteresis pattern from
-            // CObjCell::find_cell_list Position-variant at
-            // acclient_2013_pseudo_c.txt:308742-308783.
-            //
-            // Likely closes/obsoletes:
-            //   - #98 (cellar ascent stuck at last step) — direct target
-            //   - #97 (phantom collisions + fall-through on 2nd floor) —
-            //     same instability family hypothesized
-            //   - #90 (sphere-overlap workaround below) — superseded;
-            //     can be removed after visual verification (A6.P4)
-            var fallbackCell = DataCache.GetCellStruct(fallbackCellId);
-            if (fallbackCell?.CellBSP?.Root is not null)
-            {
-                var fallbackLocal = Vector3.Transform(worldPos, fallbackCell.InverseWorldTransform);
-                if (BSPQuery.PointInsideCellBsp(fallbackCell.CellBSP.Root, fallbackLocal))
-                    return fallbackCellId;  // center still inside; stick.
-            }
+            // Slice 3 work remains valuable as research evidence; the fix
+            // shape was wrong. Issue #90 stays as workaround until a
+            // better stickiness mechanism is designed (probably needs to
+            // be GATED by some "near cell boundary" check rather than
+            // applied unconditionally).
 
             // Fallback cell no longer valid → re-resolve via portal-graph BFS.
             uint indoorResult = CellTransit.FindCellList(DataCache, worldPos, sphereRadius, fallbackCellId);