<?php

use Behat\Mink\Mink,
    Behat\Mink\Session,
    Behat\Mink\Driver\Selenium2Driver;

use Selenium\Client as SeleniumClient;

$url = 'http://example.com';

$mink = new Mink(array(
    'selenium2' => new Session(new Selenium2Driver($browser, null, $url)),
));

$mink->getSession('selenium2')->getPage()->findLink('Chat')->click();