HBP theories...

[Eddie]

No: HPFGUIDX 159845

> brothergib:
> > On finding out from Flitwick that DE's have invaded the castle, Snape 
> > runs straight for the tower, without even stopping to consider the 
> > battle raging within Hogwarts.
>
> zgirnius:
> There are other Order members attempting to deal 
> with the battle. There is no other Order member who knows what Snape 
> knows, so it makes sense for him to leave them to it.

Eddie:
Remember that we don't actually know WHAT Flitwick told Snape:
* "Death Eaters in the castle, near the tower!" ?
* "Dark Mark over the tower!"  ?
* "Hurry!  Come help!  Follow me!" ?

I'm wondering why would Snape, upon seeing the battle, not join in? 
Why would Snape even think that he should go up ONTO the top of the
tower?  I may be wrong, but I don't recall any evidence that was
available/visible to Snape to indicate that the top of the tower was
important in any way.

So, all these questions push me into the "Snape knew something
beforehand" camp.  Just what, I'm uncertain.

Eddie