When using stop limits to get out of a position, set the limit really far away to make sure you're out. And no, you won't get a bad fill. It amazes me how many people say "it blew by my stop" and end up losing a ton of money; yet these same folks refuse to put on a wide limit. Remember, a market order is the same thing as a limit of infinity. So, if you want maximum speed and certainty of exiting the position, use stop/limits with the limit price set far away. It is impossible (other than a system failure) in an electronic market to be taken advantage of doing this. I do it everyday, and have never had a bad thing happen.