Board Thread:Episode Discussion/@comment-25876992-20180302194622/@comment-81.148.229.149-20180303134211

Cinder didn't get purified by Ruby's powers: she just got more unhinged.

Adam is extremely committed to vengeance, but that doesn't mean he'll reject others because their cause isn't his. He already accepted (initially under threat) a partnership with Cinder because they shared common goals, and now he has no one left, he might join Salem because he needs Salem's help to pursue his revenge against Humanity as well as to get back at Blake. And Adam will definitely not be able to kill Salem if he tried.

My guess that Salem will give him a powerup comes from Adam being pathetic in his last appearance, and Adam's Beast allusion from the Beauty and the Beast. In the (modern conceptions of) the story, the Witch/Enchantress/Fairy transformed the Prince into the Beast to reflect in his appearance the wickedness in his heart. My RWBY Theory is that Salem (the Witch) will imbue Adam (the Prince/the Beast) with Grimm, something like she did to Cinder, to give him more power, and possibly bring out his increasingly dominating primal aspect.

Now going to your speculation that Salem may give Adam the task of taking down Ruby, I don't think Ruby will activate her Silver Eyes against Adam just because he attacks her. Ruby's Silver Eyes activated from painful emotional trauma after witnessing her friends die or get hurt, and just attacking Ruby herself won't do that since Ruby's very selfless and doesn't value her life that much. Adam will have to attack somebody else close to Ruby to spur her Silver Eyes. As for the effects of her SIlver Eyes, it shouldn't be really different to what Cinder suffered.