Is it possible to pass the whole Request to another Controller from within a Controller action?

Lets say we have something like this:

The First Controller:

class Controller1 extends Page_Controller {
  public static $url_handlers = array(
    '$Action/$ID'  => 'doStuff'
  )

  function doStuff($request) {
    if($request->param['Action'] == 'special') {
       // Pass control to my SpecialController
    }
    return $this;
  }
}

The Special Controller

class SpecialController extends Page_Controller {
  public static $url_handlers = array('$ID' => 'display');

  public function display($request) {
     return $this;
  }
}

How can I do something like this? I've tried it with

return new SpecialController();

$controller = new SpecialController();
return $controller->handleRequest($request);

But all I get is:

[User Warning] popCurrent called on ModelAsController controller, but it wasn't at the top of the stack

Any solutions for this?