"It was a very shaken Severus Snape who returned to his quarters after a foreshortened dinner. For a moment, he had feared that the Headmaster would throw him to the wolves in the Ministry. He was under no illusions – Potter might be able to protect him from many things, but not, at least for the present, the Ministry.
As much as he hated to admit it, it had appeared as if Potter had anticipated every move that afternoon, which meant that he had wanted Snape to see and understand what was going on.
Why?
It suddenly dawned on Snape – it had been a warning. Not a warning not to trust Potter, but a warning not to fully trust Dumbledore. Had Dumbledore refused to step in for Snape, Snape was under few illusions. If Potter had to choose between saving the Mutt or saving him, Potter would see Snape sent off to Azkaban, at least for a while. Potter had wanted to remind Snape of that, and that he might have to make that choice. Knowing it, Snape could have still saved himself by running."
Y'see, Sev?! Alby ain't all sweetness and light!! EVIL GRIN