Its just like they said. The warlock can just take a quick step left and right or back once to get him to stop if need be. I dunno if this will help, but I threw this together for a buddy that was asking me some similar questions, but for a warrior tank.
http://www.ifilm.com/ifilmdetail/2775907
(Don't critique it, i just threw it together in an hour. Just for information. Windows Movie Maker sucks hardcore.)