diff --git a/lib/main.js b/lib/main.js
index 08b74d30..82ca97e9 100755
--- a/lib/main.js
+++ b/lib/main.js
@@ -26,15 +26,17 @@ try {
   loadDefaultChimera();
 }
 
-setInterval(webkit.processEvents, 50);
-
 var exports = module.exports;
-var timer;
-var processingEvents = true;
+var timer = 0;
+var processingEvents = false;
+var referenceCount = 0;
 
 function stop() {
-  processingEvents = false;
-  clearInterval(timer);
+  --referenceCount;
+  if (referenceCount === 0) {
+    processingEvents = false;
+    clearInterval(timer);
+  }
 };
 
 function start() {
@@ -42,6 +44,7 @@ function start() {
     processingEvents = true;
     timer = setInterval(webkit.processEvents, 50);
   }
+  ++referenceCount;
 };
 
 function Chimera(options) {
@@ -51,14 +54,7 @@ function Chimera(options) {
   var cookies = options.cookies || '';
   var disableImages = !!(options.disableImages);
   var shouldStart = false;
-  if (processingEvents) {
-    shouldStart = true;
-    // stop();
-  }
   this.browser = new webkit.Browser(userAgent, libraryCode, cookies, disableImages);
-  if (shouldStart) {
-    // start();
-  }
   var proxy = options.proxy;
   if (proxy) {
     this.setProxy(proxy.type, proxy.host, proxy.port, proxy.username, proxy.password)
@@ -112,8 +108,10 @@ Chimera.prototype.perform = function(options) {
   var locals = options.locals || {};
   var run = 'with('+JSON.stringify(locals)+'){(' + (options.run || function(callback) {callback(null, "");}) + ')(function(err,res) {window.chimera.callback(JSON.stringify(err), JSON.stringify(res));})}';
   var callback = options.callback || function(err, result) {};
+  start();
   this.browser.open(url, run, function(errStr, resStr) {
     callback(parseOrReturn(errStr), parseOrReturn(resStr));
+    stop();
   });
 }
 
diff --git a/src/browser.cc b/src/browser.cc
index 4f9d5593..42a83f6c 100644
--- a/src/browser.cc
+++ b/src/browser.cc
@@ -12,10 +12,9 @@ Browser::Browser(QString userAgent, QString libraryCode, QString cookies, bool d
   libraryCode_ = libraryCode;
   cookies_ = cookies;
   disableImages_ = disableImages;
-  chimera_ = 0;
 }
+
 Browser::~Browser() {
-  delete chimera_;
 }
 
 void Browser::Initialize(Handle<Object> target) {
@@ -51,8 +50,6 @@ Handle<Value> Browser::New(const Arguments& args) {
 void AsyncWork(uv_work_t* req) {
     BWork* work = static_cast<BWork*>(req->data);
     work->chimera->wait();
-    work->result = work->chimera->getResult();
-    work->errorResult = work->chimera->getError();
 }
 
 void AsyncAfter(uv_work_t* req) {
@@ -71,6 +68,9 @@ void AsyncAfter(uv_work_t* req) {
             node::FatalException(try_catch);
         }
     } else {
+        work->result = work->chimera->getResult();
+        work->errorResult = work->chimera->getError();
+
         const unsigned argc = 2;
         Local<Value> argv[argc] = {
             Local<Value>::New(Null()),
@@ -84,11 +84,8 @@ void AsyncAfter(uv_work_t* req) {
         }
     }
 
-    uv_queue_work(uv_default_loop(), &work->request, AsyncWork, AsyncAfter);
-
-    // TODO: we need to figure out where to dispose the callback & free up work
-    // work->callback.Dispose();
-    // delete work;
+    work->callback.Dispose();
+    delete work;
 }
 
 Handle<Value> Browser::Cookies(const Arguments& args) {
@@ -167,11 +164,10 @@ Handle<Value> Browser::Close(const Arguments& args) {
   
   Browser* w = ObjectWrap::Unwrap<Browser>(args.This());
   Chimera* chimera = w->getChimera();
- 
-  if (0 != chimera) {
+
+  if (NULL != chimera) {
     chimera->exit(1);
-    w->setChimera(0);
-    chimera->deleteLater();
+    w->setChimera(NULL);
   }
  
   return scope.Close(Undefined());
diff --git a/src/browser.h b/src/browser.h
index 736c1693..fcc7f5e0 100644
--- a/src/browser.h
+++ b/src/browser.h
@@ -1,6 +1,8 @@
 #ifndef BROWSER_H
 #define BROWSER_H
 
+#include <boost/tr1/memory.hpp>
+
 #include <node.h>
 #include <QApplication>
 #include <QTimer>
@@ -21,8 +23,8 @@ struct BWork {
 class Browser : public node::ObjectWrap {
  public:
   static void Initialize(v8::Handle<v8::Object> target);
-  Chimera* getChimera() const { return chimera_; };
-  void setChimera(Chimera *chimera) { chimera_ = chimera; };
+  Chimera* getChimera() const { return chimera_.get(); };
+  void setChimera(Chimera *chimera) { chimera_.reset(chimera); };
 
   QString userAgent() {return userAgent_; };
   QString libraryCode() {return libraryCode_; };
@@ -40,7 +42,7 @@ class Browser : public node::ObjectWrap {
   static v8::Handle<v8::Value> SetCookies(const v8::Arguments& args);
   static v8::Handle<v8::Value> SetProxy(const v8::Arguments& args);
 
-  Chimera* chimera_;
+  std::tr1::shared_ptr<Chimera> chimera_;
   QString libraryCode_;
   QString userAgent_;
   QString cookies_;
diff --git a/src/chimera.cc b/src/chimera.cc
index 1c007bcc..8b25fa3d 100644
--- a/src/chimera.cc
+++ b/src/chimera.cc
@@ -159,9 +159,9 @@ void Chimera::setEmbedScript(const QString &jscode)
 
 void Chimera::callback(const QString &errorResult, const QString &result)
 {
+  QMutexLocker locker(&m_mutex);
   m_errors.enqueue(errorResult);
   m_results.enqueue(result);
-  m_mutex.unlock();
   m_loading.wakeAll();
 }
 
@@ -174,13 +174,15 @@ void Chimera::exit(int code)
 {
     m_page.triggerAction(QWebPage::Stop);
     m_returnValue = code;
+    QMutexLocker locker(&m_mutex);
+    m_loading.wakeAll();
+    locker.unlock();
     disconnect(&m_page, SIGNAL(loadFinished(bool)), this, SLOT(finish(bool)));
 }
 
 void Chimera::execute()
 {
     std::cout << "debug -- about to lock" << std::endl;
-    m_mutex.tryLock();
     std::cout << "debug -- about to evaluate" << std::endl;
     m_page.mainFrame()->evaluateJavaScript(m_script);
     std::cout << "debug -- done evaluating" << std::endl;
@@ -207,17 +209,13 @@ void Chimera::open(const QString &address)
 {
     m_page.triggerAction(QWebPage::Stop);
     m_loadStatus = "loading";
-    m_mutex.lock();
     m_page.mainFrame()->setUrl(QUrl(address));
 }
 
 void Chimera::wait()
 {
-  if (m_mutex.tryLock()) {
-    m_mutex.unlock();
-  } else {
+    QMutexLocker locker(&m_mutex);
     m_loading.wait(&m_mutex);
-  }
 }
 
 bool Chimera::capture(const QString &fileName)
@@ -259,11 +257,19 @@ int Chimera::returnValue() const
 
 QString Chimera::getResult()
 {
+    if (m_results.isEmpty()) {
+        // TODO may cause by Browser::Close
+        return "";
+    }
     return m_results.dequeue();
 }
 
 QString Chimera::getError()
 {
+    if (m_errors.isEmpty()) {
+        // TODO may cause by Browser::Close
+        return "";
+    }
     return m_errors.dequeue();
 }