diff --git a/src/ZB.MOM.WW.MxGateway.Worker.Tests/Ipc/WorkerPipeSessionTests.cs b/src/ZB.MOM.WW.MxGateway.Worker.Tests/Ipc/WorkerPipeSessionTests.cs
index 1bef756..dca5936 100644
--- a/src/ZB.MOM.WW.MxGateway.Worker.Tests/Ipc/WorkerPipeSessionTests.cs
+++ b/src/ZB.MOM.WW.MxGateway.Worker.Tests/Ipc/WorkerPipeSessionTests.cs
@@ -1525,9 +1525,12 @@ public sealed class WorkerPipeSessionTests
         // activity timestamp stopped advancing would accumulate staleness past the ceiling and
         // fault — and require the beats to have actually flowed while it ran, so an inspection
         // that saw a couple of frames and timed out cannot pass for a clean window. None may be a
-        // WorkerFault while activity is continuously refreshed. The window stays well inside
-        // FakeRuntimeSession's 5 s dispatch-block ceiling, so the command is still in flight
-        // throughout.
+        // WorkerFault while activity is continuously refreshed. Nothing here is racing
+        // FakeRuntimeSession's blocked-dispatch backstop: that wait is a safety net sized far above
+        // any window a test opens (and above this test's own cancellation), so the command stays in
+        // flight for however long a loaded box stretches the loop. Were the two close together, a
+        // slow run would take the reply mid-window and then fail waiting for a reply already gone
+        // by — a cancellation at teardown, naming nothing.
         TimeSpan inspectionWindow = TimeSpan.FromSeconds(2);
         const int minimumFramesInspected = 30;
         Stopwatch inspection = Stopwatch.StartNew();
diff --git a/src/ZB.MOM.WW.MxGateway.Worker.Tests/TestSupport/FakeRuntimeSession.cs b/src/ZB.MOM.WW.MxGateway.Worker.Tests/TestSupport/FakeRuntimeSession.cs
index c7b9ebf..0f89658 100644
--- a/src/ZB.MOM.WW.MxGateway.Worker.Tests/TestSupport/FakeRuntimeSession.cs
+++ b/src/ZB.MOM.WW.MxGateway.Worker.Tests/TestSupport/FakeRuntimeSession.cs
@@ -20,6 +20,17 @@ namespace ZB.MOM.WW.MxGateway.Worker.Tests.TestSupport;
 /// </summary>
 internal sealed class FakeRuntimeSession : IWorkerRuntimeSession
 {
+    /// <summary>
+    ///     Backstop on the <see cref="BlockDispatch"/> wait so a test that never releases leaves no
+    ///     thread parked forever. It is a safety net, never a scenario's timing budget: nothing
+    ///     asserts on it firing, and a test whose blocked window outruns it silently gets its reply
+    ///     mid-window, which then fails as an opaque cancellation somewhere later. Kept far above
+    ///     any test's window — and above the 20 s cancellation those tests arm — so the test's own
+    ///     token always fails first, with its own message. <see cref="Dispose"/> releases the wait
+    ///     regardless, so teardown never depends on this elapsing.
+    /// </summary>
+    private static readonly TimeSpan BlockedDispatchSafetyNet = TimeSpan.FromSeconds(30);
+
     private readonly ManualResetEventSlim releaseDispatch = new(false);
     private readonly object gate = new();
     private readonly Queue<WorkerEvent> events = new();
@@ -91,7 +102,7 @@ internal sealed class FakeRuntimeSession : IWorkerRuntimeSession
 
                 if (BlockDispatch)
                 {
-                    releaseDispatch.Wait(TimeSpan.FromSeconds(5));
+                    releaseDispatch.Wait(BlockedDispatchSafetyNet);
                 }
 
                 SetSnapshot(new WorkerRuntimeHeartbeatSnapshot(