diff --git a/src/AcDream.App/Rendering/GameWindow.cs b/src/AcDream.App/Rendering/GameWindow.cs
index 55291ad..12b1c6c 100644
--- a/src/AcDream.App/Rendering/GameWindow.cs
+++ b/src/AcDream.App/Rendering/GameWindow.cs
@@ -7682,9 +7682,19 @@ public sealed class GameWindow : IDisposable
                 {
                     int seqCount = seqFrames?.Count ?? -1;
                     int setupParts = ae.Setup.Parts.Count;
-                    int animFrame0Parts = ae.Animation.PartFrames.Count > 0
-                        ? ae.Animation.PartFrames[0].Frames.Count
-                        : -1;
+                    // #62: B.4c introduced `Animation = null!` for sequencer-driven
+                    // door entities (parallel branch sites at line 2867 + 7892).
+                    // Doors don't currently enter _remoteDeadReckon, so this
+                    // path isn't reachable for them today — but the read was
+                    // unguarded and would NRE the moment something flips.
+                    // Local-var + `is not null` keeps the guard scoped: the
+                    // legacy slerp branch below treats ae.Animation as non-
+                    // null (per its non-nullable declared type) unchanged.
+                    var animMaybeNull = ae.Animation;
+                    int animFrame0Parts =
+                        animMaybeNull is not null && animMaybeNull.PartFrames.Count > 0
+                            ? animMaybeNull.PartFrames[0].Frames.Count
+                            : -1;
                     double seqHash = 0.0;
                     if (seqFrames is not null)
                     {