"My lord..." Severus began, but Voldemort cast a spell at Severus, which severed an artery in his neck – one Hermione felt as if he’d done it to her.  She bit down on her lip to keep from screaming as Snape fell back into the window.  She could see his dark form through the glass even in the non-existent light.  Then she felt a powerful block clamp down on the bond they shared, and she could no longer feel his pain.