diff --git a/src/AcDream.App/Rendering/GameWindow.cs b/src/AcDream.App/Rendering/GameWindow.cs
index 393f4e1e..d9b7ed0d 100644
--- a/src/AcDream.App/Rendering/GameWindow.cs
+++ b/src/AcDream.App/Rendering/GameWindow.cs
@@ -6790,6 +6790,11 @@ public sealed class GameWindow : IDisposable
         // _heightTable still needed for physics TerrainSurface below.
         if (_terrain is null || _dats is null || _heightTable is null) return;
 
+        // datLock fix: every dat the apply needs was pre-read by the worker into
+        // lb.PhysicsDats. Read from the bundle — NO _dats.Get here, so this method
+        // (and its caller) need no _datLock.
+        var datBundle = lb.PhysicsDats ?? AcDream.Core.World.PhysicsDatBundle.Empty;
+
         uint lbXu = (lb.LandblockId >> 24) & 0xFFu;
         uint lbYu = (lb.LandblockId >> 16) & 0xFFu;
         int lbX = (int)lbXu;
@@ -6864,21 +6869,18 @@ public sealed class GameWindow : IDisposable
 
             var cellSurfaces = new List<AcDream.Core.Physics.CellSurface>();
             var portalPlanes = new List<AcDream.Core.Physics.PortalPlane>();
-            var lbInfo = _dats.Get<DatReaderWriter.DBObjs.LandBlockInfo>(
-                (lb.LandblockId & 0xFFFF0000u) | 0xFFFEu);
+            var lbInfo = datBundle.Info;
             if (lbInfo is not null && lbInfo.NumCells > 0)
             {
                 uint firstCellId = (lb.LandblockId & 0xFFFF0000u) | 0x0100u;
                 for (uint offset = 0; offset < lbInfo.NumCells; offset++)
                 {
                     uint envCellId = firstCellId + offset;
-                    var envCell = _dats.Get<DatReaderWriter.DBObjs.EnvCell>(envCellId);
-                    if (envCell is null) continue;
+                    if (!datBundle.EnvCells.TryGetValue(envCellId, out var envCell)) continue;
                     if (envCell.EnvironmentId == 0) continue;
 
-                    var environment = _dats.Get<DatReaderWriter.DBObjs.Environment>(
-                        0x0D000000u | envCell.EnvironmentId);
-                    if (environment is null) continue;
+                    if (!datBundle.Environments.TryGetValue(
+                        0x0D000000u | envCell.EnvironmentId, out var environment)) continue;
                     if (!environment.Cells.TryGetValue(envCell.CellStructure, out var cellStruct)) continue;
 
                     // Transform CellStruct vertices from cell-local to world space.
@@ -6991,7 +6993,7 @@ public sealed class GameWindow : IDisposable
                         // _dats is non-null on every streaming-drain path
                         // (the GfxObj physics cache loop below dereferences
                         // it unconditionally).
-                        var bldSetup = _dats!.Get<DatReaderWriter.DBObjs.Setup>(building.ModelId);
+                        datBundle.Setups.TryGetValue(building.ModelId, out var bldSetup);
                         shellPart0 = bldSetup is not null && bldSetup.Parts.Count > 0
                             ? bldSetup.Parts[0]
                             : 0u;
@@ -7067,8 +7069,7 @@ public sealed class GameWindow : IDisposable
             foreach (var meshRef in entity.MeshRefs)
             {
                 if ((meshRef.GfxObjId & 0xFF000000u) != 0x01000000u) continue;
-                var gfx = _dats.Get<DatReaderWriter.DBObjs.GfxObj>(meshRef.GfxObjId);
-                if (gfx is null) continue;
+                if (!datBundle.GfxObjs.TryGetValue(meshRef.GfxObjId, out var gfx)) continue;
                 _physicsDataCache.CacheGfxObj(meshRef.GfxObjId, gfx);
             }
         }
@@ -7104,7 +7105,7 @@ public sealed class GameWindow : IDisposable
                 uint src = entity.SourceGfxObjOrSetupId;
                 if ((src & 0xFF000000u) == 0x02000000u)
                 {
-                    var datSetup = _dats.Get<DatReaderWriter.DBObjs.Setup>(src);
+                    datBundle.Setups.TryGetValue(src, out var datSetup);
                     if (datSetup is not null && datSetup.Lights.Count > 0)
                     {
                         var loaded = AcDream.Core.Lighting.LightInfoLoader.Load(