She knew her approach was futile, she knew there was nothing else she could do, and that they were going to die at the jaws of their professor. At the very least, if they didn't die, they would be infected with Lycanthropy, spending the remainder of their lives suffering from monthly transformations. Hermione grieved for her professor, he wouldn't be able to live with himself once he discovered he had attacked Harry, the son of his best friend.