Okay, so as I understand it, Rukhor's plan was:

1. Release Shelob into Middle-Earth
2. Shelob goes on rampage and eats everyone
3. Profit

Okay, great. Question: what exactly was his plan for not being in the "everyone" category listed in step 2? I may have missed something in the quests, and imagine it has to do with the fact that his minions have their blood removed, but I'd imagine he thought that far ahead, right?