Board Thread:Spoilers!/@comment-2153169-20140913181317/@comment-24674051-20141111182154

I can only think of one person that he would do anything to (Kill or other nefarious activity) and have any real pleasure about it. And that would be Killian.

However, we don't know anything (yet) about what Ingrid whispered. All we know that this is the one last piece of the Hat Puzzle that he needs to accomplish. Whatever it is, He would be fairly excited about it, if it means severing the Dagger's control while allowing him to retain his power.