Lupin's Shiver When Confroted by Hermione's Accusations in PoA

[hedge2staxy <hodgins@ssi.net>]

No: HPFGUIDX 49361

This shiver that Lupin gives when responding to Hermione's 
accusations in the Shrieking Shack has been on my mind.  What might 
it mean? 
"I have not been helping Sirius get into the castle and I certainly 
don't want Harry dead..." An odd shiver passed over his face.  But I 
won't deny that I am a werewolf."(quoting Lupin on p.345 of the 
American Hardcover version)

It does seem to support a number of theories out there, including:

a) Lupin traded bodies with James before he was killed and now James 
(in Lupin's body), who would want to protect Harry above all other 
things, shivers at even the thought that he would ever harm his 
beloved son.

b) Is Lupin being less than honest?  Does the shiver signify that 
under some, yet unknown circumstances, he would consider harming 
Harry?  Perhaps, the ultimate destruction of Voldemort may require 
the death of Harry (forgive the Savior concept) and Lupin foresees 
this possible sacrifice.

c) Maybe the shiver only relates to his distaste at having to reveal 
his condition of werewolf to Harry and Ron.

I'm fishing around here.  Have others been struck by this line?

-Hedgehog2000