diff --git a/YesNt.Interpreter.Tests/AssemblyInfo.cs b/YesNt.Interpreter.Tests/AssemblyInfo.cs
new file mode 100644
index 0000000..38707ae
--- /dev/null
+++ b/YesNt.Interpreter.Tests/AssemblyInfo.cs
@@ -0,0 +1,3 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+[assembly: Parallelize(Workers = 0, Scope = ExecutionScope.MethodLevel)]
diff --git a/YesNt.Interpreter.Tests/ConsoleStatementsTests.cs b/YesNt.Interpreter.Tests/ConsoleStatementsTests.cs
index 61ddae7..1ba7cbc 100644
--- a/YesNt.Interpreter.Tests/ConsoleStatementsTests.cs
+++ b/YesNt.Interpreter.Tests/ConsoleStatementsTests.cs
@@ -76,6 +76,7 @@ public class ConsoleStatementsTests
     }
 
     [TestMethod]
+    [DoNotParallelize] // timing-sensitive: relies on Thread.Sleep to let the interpreter reach %read_key
     public void ReadKeyCanBeInterruptedByStopTest()
     {
         YesNtInterpreter interpreter = new YesNtInterpreter();
diff --git a/YesNt.Interpreter/Runtime/RuntimeInformation.cs b/YesNt.Interpreter/Runtime/RuntimeInformation.cs
index 862735a..371ed94 100644
--- a/YesNt.Interpreter/Runtime/RuntimeInformation.cs
+++ b/YesNt.Interpreter/Runtime/RuntimeInformation.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading;
 
 using YesNt.Interpreter.Utilities;
 
@@ -191,7 +192,7 @@ internal sealed class RuntimeInformation
         IsLocalSearch = false;
         LineNumber = 0;
 #pragma warning disable S2696 // internalTaskId is a shared counter intentionally incremented by each Reset call
-        TaskId = ++internalTaskId;
+        TaskId = Interlocked.Increment(ref internalTaskId);
 #pragma warning restore S2696
     }