diff --git a/Library/Core/Blocks/Controls/ControlsRepeatExt.cs b/Library/Core/Blocks/Controls/ControlsRepeatExt.cs
index a7628b8..08dbbcb 100644
--- a/Library/Core/Blocks/Controls/ControlsRepeatExt.cs
+++ b/Library/Core/Blocks/Controls/ControlsRepeatExt.cs
@@ -24,19 +24,14 @@ public class ControlsRepeatExt : Block
 
       await statement.EvaluateAsync(context);
 
-      try
-      {
-        /* See if a break of the loop is requested. */
-        if (context.EscapeMode == EscapeMode.Break) break;
-      }
-      finally
-      {
-        /* Either a continue is requested or the inner block is executed normally. */
-        context.EscapeMode = EscapeMode.None;
-      }
+      /* See if a break of the loop is requested. */
+      if (context.EscapeMode == EscapeMode.Break) break;
+
+      /* Either a continue is requested or the inner block is executed normally. */
+      context.EscapeMode = EscapeMode.None;
     }
 
-    /* For safety reasons reset the break mode - should not really be neccessary! */
+    /* Reset the break mode - just in case. */
     context.EscapeMode = EscapeMode.None;
 
     /* Continue with the next block. */
diff --git a/Library/Core/Blocks/Controls/ControlsWhileUntil.cs b/Library/Core/Blocks/Controls/ControlsWhileUntil.cs
index d017aa8..780145e 100644
--- a/Library/Core/Blocks/Controls/ControlsWhileUntil.cs
+++ b/Library/Core/Blocks/Controls/ControlsWhileUntil.cs
@@ -1,5 +1,3 @@
-
-
 using BlocklyNet.Core.Model;
 
 namespace BlocklyNet.Core.Blocks.Controls;
@@ -12,36 +10,43 @@ public class ControlsWhileUntil : Block
   /// <inheritdoc/>
   public override async Task<object?> EvaluateAsync(Context context)
   {
-    var mode = Fields["MODE"];
     var value = Values.TryGet("BOOL");
+    var statement = Statements.TryGet("DO");
 
-    if (!Statements.Has("DO") || null == value)
+    if (statement == null || null == value)
       return await base.EvaluateAsync(context);
 
-    var statement = Statements["DO"];
+    var execStatementAndTestForBreak = async () =>
+    {
+      context.Cancellation.ThrowIfCancellationRequested();
+
+      await statement.EvaluateAsync(context);
+
+      if (context.EscapeMode == EscapeMode.Break) return true;
+
+      context.EscapeMode = EscapeMode.None;
+
+      return false;
+    };
 
-    if (mode == "WHILE")
+    switch (Fields["MODE"])
     {
-      while ((bool)(await value.EvaluateAsync(context))!)
-      {
-        context.Cancellation.ThrowIfCancellationRequested();
-
-        if (context.EscapeMode == EscapeMode.Break)
-        {
-          context.EscapeMode = EscapeMode.None;
-          break;
-        }
-
-        await statement.EvaluateAsync(context);
-      }
+      case "WHILE":
+        while ((bool)(await value.EvaluateAsync(context))!)
+          if (await execStatementAndTestForBreak())
+            break;
+
+        break;
+      case "UNTIL":
+        do
+          if (await execStatementAndTestForBreak())
+            break;
+        while (!(bool)(await value.EvaluateAsync(context))!);
+
+        break;
     }
-    else
-      while (!(bool)(await value.EvaluateAsync(context))!)
-      {
-        context.Cancellation.ThrowIfCancellationRequested();
 
-        await statement.EvaluateAsync(context);
-      }
+    context.EscapeMode = EscapeMode.None;
 
     return await base.EvaluateAsync(context);
   }