Changes after lethally feeding

Susan let out a whimper and a groan, moving fitfully. By chance, her mouth brushed against my forearm, still stained with drying blood. She froze, completely, her whole body shuddering. She looked up at me with those dark, huge eyes, her face twisting with need. She moved toward my arm again, and I jerked it back from her mouth.
"Susan," I said. "Wait."
"What was that?" she whispered. "That was good." She shivered again and rolled to all fours, eyes slowly focusing on me.
I shot a glance toward Justine, but only saw her feet as she pulled them back to her, slipping back into the tiny space between the washing machine and the wall. I turned back to Susan, who was coming toward me, staring as though blind, on all fours.
I backed away from her, and fumbled out to my side with one hand. I found the bloodstained towel I'd been using before, and threw it at her. She stopped for a moment, staring, and then lowered her face with a groan, beginning to lick at the towel.
I scooted back on all fours, getting away from her, still dizzy. "Justine," I hissed. "What do we do?"
"There's nothing to do," Justine whispered. "We can't get out. She isn't herself. Once she kills, she'll be gone."
I flashed a glance at her over my shoulder. "Once she kills? What do you mean?"
Justine watched me with solemn eyes. "Once she kills. She's different. But she isn't quite like them until it's complete. Until she's killed someone feeding on them. That's the way the Reds work."
"So she's still Susan?"
Justine shrugged again, her expression disinterested. "Sort of."


Grave Peril, Page 393