diff --git a/SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs b/SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs
index 4f0d88c..acababe 100644
--- a/SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs
+++ b/SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs
@@ -218,8 +218,7 @@ public class BattleNodeFlowTests
         await using var _b = clientB;
         await Task.WhenAll(clientA.ConsumeHandshakeAsync(ct), clientB.ConsumeHandshakeAsync(ct));
 
-        await DriveHandshakeAsync(clientA, vidA, key, ct);
-        await DriveHandshakeAsync(clientB, vidB, key, ct);
+        await DrivePvpHandshakeAsync(clientA, vidA, clientB, vidB, key, ct);
 
         // Both are now AfterReady. A sends TurnEnd; both should receive TurnEnd + Judge.
         await clientA.SendMsgAsync(MakeEnvelopeWith(vidA, NetworkBattleUri.TurnEnd, pubSeq: 5), key, ct);
@@ -268,8 +267,7 @@ public class BattleNodeFlowTests
         await using var _a = clientA;
         await using var _b = clientB;
         await Task.WhenAll(clientA.ConsumeHandshakeAsync(ct), clientB.ConsumeHandshakeAsync(ct));
-        await DriveHandshakeAsync(clientA, vidA, key, ct);
-        await DriveHandshakeAsync(clientB, vidB, key, ct);
+        await DrivePvpHandshakeAsync(clientA, vidA, clientB, vidB, key, ct);
 
         // A retires.
         await clientA.SendMsgAsync(MakeEnvelopeWith(vidA, NetworkBattleUri.Retire, pubSeq: 5), key, ct);
@@ -314,8 +312,7 @@ public class BattleNodeFlowTests
         var (clientA, clientB) = await ConnectBothAsync(factory, pending.BattleId, vidA, vidB, key, ct);
         await using var _b = clientB;
         await Task.WhenAll(clientA.ConsumeHandshakeAsync(ct), clientB.ConsumeHandshakeAsync(ct));
-        await DriveHandshakeAsync(clientA, vidA, key, ct);
-        await DriveHandshakeAsync(clientB, vidB, key, ct);
+        await DrivePvpHandshakeAsync(clientA, vidA, clientB, vidB, key, ct);
 
         // Abruptly close A's WS (no Retire).
         await clientA.DisposeAsync();
@@ -492,7 +489,10 @@ public class BattleNodeFlowTests
 
     // -- helpers -------------------------------------------------------------
 
-    private static async Task DriveHandshakeAsync(
+    /// <summary>Drives one PvP client from InitNetwork through Swap, stopping at the
+    /// SwapResponse. Ready is NOT received here — the mulligan barrier withholds it until
+    /// BOTH sides have swapped, so the caller drains it after driving both sides.</summary>
+    private static async Task DriveThroughSwapAsync(
         RawSocketIoTestClient client, long vid, string key, CancellationToken ct)
     {
         long pubSeq = 1;
@@ -507,7 +507,23 @@ public class BattleNodeFlowTests
         await client.SendMsgAsync(MakeEnvelopeWith(vid, NetworkBattleUri.Swap, pubSeq++,
             body: new Dictionary<string, object?> { ["idxList"] = new List<object?>() }), key, ct);
         await client.ReceiveSynchronizeAsync(ct); // Swap response
-        await client.ReceiveSynchronizeAsync(ct); // Ready
+    }
+
+    /// <summary>Drives both PvP clients through the full handshake including the mulligan
+    /// barrier: each side swaps first (Ready withheld), then the second swap releases Ready
+    /// to both. Leaves both at AfterReady with pubSeq up to 4 consumed per client.</summary>
+    private static async Task DrivePvpHandshakeAsync(
+        RawSocketIoTestClient clientA, long vidA,
+        RawSocketIoTestClient clientB, long vidB, string key, CancellationToken ct)
+    {
+        await DriveThroughSwapAsync(clientA, vidA, key, ct);
+        await DriveThroughSwapAsync(clientB, vidB, key, ct);
+
+        // B's Swap (the second) releases Ready to both sides.
+        var aReady = await clientA.ReceiveSynchronizeAsync(ct);
+        Assert.That(aReady.Uri, Is.EqualTo(NetworkBattleUri.Ready));
+        var bReady = await clientB.ReceiveSynchronizeAsync(ct);
+        Assert.That(bReady.Uri, Is.EqualTo(NetworkBattleUri.Ready));
     }
 
     private static async Task<(RawSocketIoTestClient, RawSocketIoTestClient)> ConnectBothAsync(