diff --git a/TUnit.Engine/Services/EventReceiverOrchestrator.cs b/TUnit.Engine/Services/EventReceiverOrchestrator.cs
index 8e03ef52ad..050d4e4ec1 100644
--- a/TUnit.Engine/Services/EventReceiverOrchestrator.cs
+++ b/TUnit.Engine/Services/EventReceiverOrchestrator.cs
@@ -317,6 +317,11 @@ public ValueTask InvokeFirstTestInSessionEventReceiversAsync(
             return default;
         }
 
+        if (_firstTestInSessionTasks.TryGetValue("session", out var existingTask))
+        {
+            return new ValueTask(existingTask);
+        }
+
         var task = _firstTestInSessionTasks.GetOrAdd("session",
             _ => InvokeFirstTestInSessionEventReceiversCoreAsync(context, sessionContext, cancellationToken));
         return new ValueTask(task);
@@ -347,6 +352,12 @@ public ValueTask InvokeFirstTestInAssemblyEventReceiversAsync(
         }
 
         var assemblyName = assemblyContext.Assembly.GetName().FullName ?? "";
+
+        if (_firstTestInAssemblyTasks.TryGetValue(assemblyName, out var existingTask))
+        {
+            return new ValueTask(existingTask);
+        }
+
         var task = _firstTestInAssemblyTasks.GetOrAdd(assemblyName,
             _ => InvokeFirstTestInAssemblyEventReceiversCoreAsync(context, assemblyContext, cancellationToken));
         return new ValueTask(task);
@@ -377,6 +388,12 @@ public ValueTask InvokeFirstTestInClassEventReceiversAsync(
         }
 
         var classType = classContext.ClassType;
+
+        if (_firstTestInClassTasks.TryGetValue(classType, out var existingTask))
+        {
+            return new ValueTask(existingTask);
+        }
+
         var task = _firstTestInClassTasks.GetOrAdd(classType,
             _ => InvokeFirstTestInClassEventReceiversCoreAsync(context, classContext, cancellationToken));
         return new ValueTask(task);
@@ -448,7 +465,12 @@ public ValueTask InvokeLastTestInAssemblyEventReceiversAsync(
 
         var assemblyName = assemblyContext.Assembly.GetName().FullName ?? "";
 
-        var assemblyCount = _assemblyTestCounts.GetOrAdd(assemblyName, static _ => new Counter()).Decrement();
+        if (!_assemblyTestCounts.TryGetValue(assemblyName, out var assemblyCounter))
+        {
+            assemblyCounter = _assemblyTestCounts.GetOrAdd(assemblyName, static _ => new Counter());
+        }
+
+        var assemblyCount = assemblyCounter.Decrement();
 
         if (assemblyCount == 0)
         {
@@ -491,7 +513,12 @@ public ValueTask InvokeLastTestInClassEventReceiversAsync(
 
         var classType = classContext.ClassType;
 
-        var classCount = _classTestCounts.GetOrAdd(classType, static _ => new Counter()).Decrement();
+        if (!_classTestCounts.TryGetValue(classType, out var classCounter))
+        {
+            classCounter = _classTestCounts.GetOrAdd(classType, static _ => new Counter());
+        }
+
+        var classCount = classCounter.Decrement();
 
         if (classCount == 0)
         {
@@ -536,13 +563,21 @@ public void InitializeTestCounts(IEnumerable<TestContext> allTestContexts)
 
         foreach (var group in contexts.GroupBy(c => c.ClassContext.AssemblyContext.Assembly.GetName().FullName))
         {
-            var counter = _assemblyTestCounts.GetOrAdd(group.Key, static _ => new Counter());
+            if (!_assemblyTestCounts.TryGetValue(group.Key, out var counter))
+            {
+                counter = _assemblyTestCounts.GetOrAdd(group.Key, static _ => new Counter());
+            }
+
             counter.Add(group.Count());
         }
 
         foreach (var group in contexts.GroupBy(c => c.ClassContext.ClassType))
         {
-            var counter = _classTestCounts.GetOrAdd(group.Key, static _ => new Counter());
+            if (!_classTestCounts.TryGetValue(group.Key, out var counter))
+            {
+                counter = _classTestCounts.GetOrAdd(group.Key, static _ => new Counter());
+            }
+
             counter.Add(group.Count());
         }
     }
diff --git a/TUnit.Engine/Services/HookDelegateBuilder.cs b/TUnit.Engine/Services/HookDelegateBuilder.cs
index e367e7a347..6f78f1a99a 100644
--- a/TUnit.Engine/Services/HookDelegateBuilder.cs
+++ b/TUnit.Engine/Services/HookDelegateBuilder.cs
@@ -50,7 +50,7 @@ public HookDelegateBuilder(EventReceiverOrchestrator eventReceiverOrchestrator,
 
     private static Type GetCachedGenericTypeDefinition(Type type)
     {
-        return _genericTypeDefinitionCache.GetOrAdd(type, t => t.GetGenericTypeDefinition());
+        return _genericTypeDefinitionCache.GetOrAdd(type, static t => t.GetGenericTypeDefinition());
     }
 
     public async ValueTask InitializeAsync()
diff --git a/TUnit.Engine/Services/TestExecution/TestExecutionGuard.cs b/TUnit.Engine/Services/TestExecution/TestExecutionGuard.cs
index 78126112b6..06ac0c688c 100644
--- a/TUnit.Engine/Services/TestExecution/TestExecutionGuard.cs
+++ b/TUnit.Engine/Services/TestExecution/TestExecutionGuard.cs
@@ -12,8 +12,14 @@ internal sealed class TestExecutionGuard
 
     public ValueTask<bool> TryStartExecutionAsync(string testId, Func<ValueTask> executionFunc)
     {
+        // Fast path: check if test is already executing without allocating a TCS
+        if (_executingTests.TryGetValue(testId, out var existingTcs))
+        {
+            return new ValueTask<bool>(WaitForExistingExecutionAsync(existingTcs));
+        }
+
         var tcs = new TaskCompletionSource<bool>();
-        var existingTcs = _executingTests.GetOrAdd(testId, tcs);
+        existingTcs = _executingTests.GetOrAdd(testId, tcs);
 
         if (existingTcs != tcs)
         {