XML fixing escaped entities

I read an xml file if there is an escape entity I would like to fix that before I do some processing and write the xml file back. Here is what I'm doing:

    try
{

 var doc = new XmlDocument();
// do some job

}

catch (Exception e)
{
   if (e is XmlException)
   {
     checkXML(doc);
   }
  else
  {
   // do some job 
  }
}

finally
{

  _watcher.EnableRaisingEvents = true;
   GC.Collect();
    GC.WaitForPendingFinalizers();
    GC.Collect();
 }

 public void checkXML(XmlDocument doc)
        {
            XmlNode node;

            node = doc.SelectSingleNode("/BroadcastMonitor/Current");
            node["name1"].InnerText = SecurityElement.Escape(node["name1"].InnerText);
            node["name2"].InnerText = SecurityElement.Escape(node["name2"].InnerText); ;


        }

---

My First question: I can't access the doc instance in the catch. How do I access the doc instance to pass it to checkXML

My Second question: After fixing the escape elements I want to return to the try block to do continue with the job that needs to be done on the xml file. How is this possible, or do I use nested try / catch.

Kindly explain. Thank you.