I plan on throwing some Enslavers at my players and wanted to be sure I understood the rules correctly. If the player looses the opposed WP check for Domination or Enslavement he's controlled for the duration of the power and he doesn't get a chance to break it? I'm used to D&D where a player gets a new save each round to break free, but that's not the case in DH?

You get one shot.

Dark Heresy is mean. Enslavers, utterly terrifying.

If the GM is exceptionally nice, he might allow the player to burn a fate point to try to break control. Of course the player should have to spend a few rounds attacking his party first. It just wouldn't be fair to the Enslavers otherwise.

Awesome, this will be a great climax to the campaign.

Thanks for the reply.