No matter what, I get a pretty Slim Application Error, with a 500 header

slim_still_generates_pretty_exception.php

<?php

// ...

$loggerSettings = array(
    'path' => APPLICATION_PATH . '/api/logs'
);
$app = new Slim(array(
    'mode'          => APPLICATION_ENV,
    'debug'         => false,
    'log.enable'    => true,
    'log.writer'    => new DateTimeFileWriter($loggerSettings)
));

// ...

$app->config('debug', false);
$app->error(function (\Exception $exception) use ($app) {
    die(var_dump($exception));
});

// ...

try {
    // Run Slim
    $app->response()->header('Content-Type', 'application/json; charset=utf-8');

    // die(var_dump($app->config('debug')); => bool(false)

    $app->run();
} catch(\Exception $e) {
    die(var_dump($e));
}

/**
 * Still, I get a pretty Slim Application Error!
 * 
 * And I get this in my log file also:
 *
 *     ERROR - 2013-04-24T12:40:30-04:00 - exception 'Slim\Exception\Stop' in [...]/api/vendor/slim/slim/Slim/Slim.php:927
 *     Stack trace:
 *     #0 [...]/api/vendor/slim/slim/Slim/Slim.php(947): Slim\Slim->stop()
 *     #1 [...]/api/core/App/Middleware/MustBeLoggedIn.php(37): Slim\Slim->halt(401, 'You must be log...')
 *     #2 [...]/api/core/App/Middleware/MustHaveRequestNonce.php(50): App\Middleware\MustBeLoggedIn->call()
 *     #3 [...]/api/vendor/slim/slim/Slim/Middleware/PrettyExceptions.php(67): App\Middleware\MustHaveRequestNonce->call()
 *     #4 [...]/api/vendor/slim/slim/Slim/Slim.php(1174): Slim\Middleware\PrettyExceptions->call()
 *     #5 [...]/api/api.php(543): Slim\Slim->run()
 *     #6 {main}
 */