Could Snape ever be a hero?

[david_p2002ca]

No: HPFGUIDX 135579

I have one slight hope for Snape yet.  As he fled the grounds of 
Hogwarts after killing DD, he gave Harry one last piece of advice - an 
odd thing for a true villain to do:

"Blocked again, and again, and again until you learnto keep your mouth 
shut and your mind closed, Potter!" sneered Snape... (page 562, UK 
edition).  If Snape is truly evil, why would he feed Harry advice 
about how to defeat him or defeat He-Who-Must-Not-Be-Named?  It's a 
small thing, but it hints that Snape's true loyalty may not be with 
HWMNBN... in fact, my impression is that Snape's loyalty is all to 
Snape and Snape alone.

David