Occlumency and Shield Charm

[frost_indri]

No: HPFGUIDX 89393

Sigune:
> I have been wondering lately about what happened in the one before 
> last of Harry's Occlumency lessons. There, Harry casts a Shield 
Charm 
> and the result is he gets to see some of Snape's memories. What I 
> find strange is that something like a simple (?) Shield Charm 
should 
> permit Harry to get inside Snape's mind. 
<snippy>
 So can Snape really rely on this Occlumency business? 
> Or does anyone have an alternative explanation for what happened?

Frost:
  Well lets try this theory on and see if it fits. 
  When trying to teach occlumency you're guard is going to be down a 
bit.  Snape prepares for this by putting some of his most personal 
memories in the pensive.  Part of this could be that to use the 
Legilimens spell that Snape was using is kind of like a full, head 
on thrust with a sword. It leaves you wide open for attacks.  So 
when Harry used the unexpected shield spell, Snape was caught with 
his gaurd down and his mind exposed, and Harry could see in.  

  So if Snape were having a Legilimens sparring match with the Dark 
Lord, then he would probably be in trouble.  But normally Snape 
isn't as exposed as he is in his lessons with Potter, so we don't 
have to worry too much about Voldie snaking though his defenses that 
way.  However, there does always remain the possibility that LV will 
get in from some other direction, that Snape breaks down, that his 
and Harry's renewed (and unreasonable on both sides) hatred at the 
end of OoP causes him to switch sides just enough to take a swipe at 
that snotty lil' brat. (as Snape sees him.)