Why?

Okay...so going back to Black Magic Sanction by Kim Harrison.  Remember that chapter with the sprawling narrative that annoyed me so much?  Well, there's another thing that annoyed me about that scene.

So after Pierce is done explaining the whole theory behind ley line physics, he proceeds to demonstrate the theory with Rachel.  All of a sudden in pops Al because he 'felt' Rachel in the lines and wanted to make sure she wasn't being kidnapped again. Then Nick inconveniently shows up, Al snags Nick, Rachel talks him down with idle threats, and Al disappears.  Well, then Rachel really is kidnapped. 

So....I have two problems, well actually three, with that whole scene.  First - there's the narrative which I've already discussed with y'all.  The second problem I have is why the whole exchange between Nick and Al?  Who cares?  What is the purpose?  Is it to prove that Al is still a mean old demon?  To prove that he hasn't gone soft?  Or is it to prove that Rachel is really still tough as beans and holds sway over Al's decisions?  I mean, what's really going on here?  It's not moving the story forward, there's nothing going on here, and it's just really not adding anything to the story.  Who knows, maybe it becomes important later.  So then there's the third thing, when Rachel really does get kidnapped - where's Al?  I mean, first of all, he's peeved that Pierce is teaching her stuff, so if he thinks he's still doing that, he's going to pop in to give Pierce what for. If he wants to see if Rachel has been kidnapped, he'd pop in for that.  But he doesn't actually show up until Rachel calls him and then, when she does, he acts all surprised that she's calling. 

So that brings me to the question...why?  Why is that scene even there?