Grimacing as she sees her brother climax in the monster's grip, she thinks about the offer.  "So...seven..." she grits her teeth "breedings?  Then we're both free?  And how do I know you'll keep up your end of the bargain?  Is there some way to seal the deal?"  While she may not be crazy about the idea of spending weeks with these things, it's better to ensure their escape now than to place her trust in these monsters.