"Yes," Angel said. "In mystical terms, Spike is part of me. If the Senior Partners kill me... he dies too."

What happens if someone other than the Senior Partners kills Angel? Or if someone kills Spike? Not really seeing the down side for the Forces of Evil here.

Got to say, I think this is the dumbest plan Angel has come up with since killing Willow's goldfish. And agreeing to it is the dumbest thing Spike's done since mistaking Lindsey for Doyle.

Apart from the dumbness of that plan (for which I blame Angel, not you) it's another intriguing, superbly-written, chapter.