Snapedom

I was reading a fanfic about a "steam of consciousness" Severus had after the Shrieking Shack incident in PoA. At the very end of the story the author says this in her notes:

'Oh and it's even worse than that, of course, because Snape doesn't know - and probably will never know - that when he was knocked out in the Shrieking Shack, and bashed his head against the wall, nobody even bothered to check his pulse to see if he was OK - and Sirius took the opportunity to knock an injured and unconscious man around some more and nobody bothered to stop him.'

That made me think of other times Snape put himself into physical and emotional danger when shielding Harry, starting with the first book, when Hermione set him on fire, thinking she was saving Harry from falling. But the worst had to be, to my mind, in OotP, when Severus was teaching Harry Occlumency. For surely, since Voldemort could invade Harry's mind via the Horcrux in his head when looking at Dumbledore, he must have been able to see Severus teaching Harry how to resist him? Wouldn't it have been lethal to him to be found out? What do others on this site think?

Oh, btw, although it's not Friday, the story I was reading was "Yggdrasil" on White Hound Fiction: the link's below, and it's an excellent look at Snape's thoughts.

http://members.madasafish.com/~cj_whitehound/Fanfic/index.htm

Alison