Excellent advice here. If it's on a subdomain, the subdomain can be claimed in GWT as its own site. You can put a robots.txt on the subdomain then request the entire subdomain be removed from the index.
You may want to go one step further and use something like PolePosition's Code Monitor that checks the code of any page once per day and alerts you if there's a change. In a similar situation, I had it monitor the robots.txt for the live and all development sites for where I was working, so I knew if the developers changed something and could react quickly.