Snape in the Shrieking Shack (was re:time-turning)

[Hannah]

No: HPFGUIDX 112737

The Other Cheryl wrote:
<snip>
He (Snape) sits through the explanation, right up until the Prank is 
mentioned. Only then does he step out...and then he ties up LUPIN. 
Not Sirius, Lupin. 
<snip>
>He taunts Sirius, threatening to summon the Dementors immediately, 
but would he? Would Snape, cool, cautious, clever Snape, have risked 
Dumbledore's good will like that? Risked loosing DD's faith in him? 
I think he listened to the story and wondered, until the reminder of 
the Prank recalled to mind that Lupin hadn't taken his potion. So he 
secures Lupin and resolves to take Sirius and the group to DD. 

>Doing so is a win-win scenario for Snape. If the tale is a lie, he 
wins over his schoolboy rivals, permanently, and has saved the 
Potter brat in a way the boy can't deny. If it's true, his hated 
rivals are safe, and owe him a debt. He's still a hero, for bringing 
them in and capturing the real villain, if the rat really is 
Pettigrew. Either way he still has DD's favor and the boy owes him a 
debt, canceling out Snapes' debt to James. 
> 
Hannah: I really like this theory, so I'm loathe to point out any 
problems.  But the trouble is, although Lupin does say about the 
marauders being animagi, he never says what animal Pettigrew was, 
never says Pettigrew was the traitor, and never says anything about 
him being right there, as 'Scabbers the rat'.  Snape never hears 
that, and it would take quite a leap of the imagination to guess 
it.  

>Cheryl: And, remember, Snape is a superb occulamens, who can tell 
when he's 
> being lied to. He has to be trying to use it there, if for no 
other reason than to come up with evidence to support his side.

Hannah: That's interesting.  I'd always taken occlumency as being 
separate from legilimency, so although Snape is brilliant at 
blocking his thoughts, he isn't necessarily as good at reading those 
of others.  Harry has lied to him a few times and Snape's never 
*seemed* to use legilimency.  But maybe the two go together - has 
anyone worked out if they do or not?

Cheryl continued:
<snip>
He (Snape) has to seem upset (on discovering Sirius gone), so he 
rants. 
He then heads to the Hospital wing, too curious to let it rest. And 
DD tells him how it was done. "Unless you are suggesting that Harry 
and Hermione are able to be in two places at once". Snape glares, 
then storms out...he now knows how it was done. Hermione's time-
turner. Not DD's answer. Snape only accused HARRY. He never 
mentioned Hermione. So, why did DD mention her if not to clue in 
> Snape? 

Hannah: I'd never noticed how DD seems to explain before, but you're 
right. Snape probably would have known, as a teacher, about Hermione 
having the time turner. I'm still not sure when Snape realised that 
Black was innocent - if it was after this scene, or before.  Once he 
sees that DD is convinced, maybe he just decides to give in.  My 
original theory was that he knew Sirius was innocent all along (from 
just after GH), but decided not to say anything in revenge for 'the 
prank.'