Was this really happening? Was Dawn actually behaving so retardedly that she was going to sacrifice herself for him? Spike wasn't going to stand for that. He wasn't worth the sacrifice. He was barely worth anything at all. Nostrils flared, Spike shook his head and growled, "No. This is my bloody soul, all right? I don't want it to go back to my body! I want to stay here! You can't just go around thrusting a blokes soul in a place that he doesn't want it put, now can you?" That was a weak argument. If it weren't true, then Spike wouldn't be stuck here, now would he?
"You're not making deals with him," Spike whirled around to look at Dawn yet again. "You are not. He asks for one favor, it turns into two. And who's to say that this favor won't be all about you going back on over to kill Buffy? He's evil, Dawn. Whatever it is that he's going to ask of you, it won't be good! You can't make a deal with him!"
He knew that neither of the two weren't listening. Dawn was stubborn, and sometimes a bit foolish, and Lucifer was...well, he was Lucifer. Jaw clenched, Spike's fingers curled into fists and he shook his head. There was no way that he was going to let Dawn get herself into a mess with him. He'd rather live a hundred deaths. And then some. So, without thinking twice (although he really should have), Spike launched himself at Lucifer, ready to hit every square inch of his body that he could get his hands on. "I'm not going to let you manipulate her into one of your bloody traps, you fucking wanker!"