Those two kills might not be the same. The first one they charged in with a knife and would probably discribe it as beast-like. Medusa/Naga/Snake-Vampire was far more subtle, and the knife she had was taken from the victim.

Copy and pasted here -
"How dull... how terribly, awfully dull...." thought Khazaar. He sat at a table, deep in the compound. "Administrative duty, what luck to be assigned this..." There was a knock at the door to his front. "In," he told the visitor. When there was no response for about ten seconds, he repeated himself, only louder. He got off his chair, irritated, and walked towards the door. Upon his hand touching the knob, the door exploded with force. The visitor had lowered it's shoulder and charged through the door, splintering it and knocking Khazaar back. It snarled angrily, swinging a knife into Khazaar's shoulder. Taking advantage, it tackled Khazaar to the floor, jaws snapping into his face, the knife being brought to bear repeatedly into his torso. The butchery continued well past the point Khazaar had ceased resisting, lasting for nearly 10 minutes as the intruder carved the body beyond recognition.....
Captain C was idling his time away in his quarters. Patrol was necessary, sure, but couldn't he at least get a different patrol every now and then? For now, he was burning time by carving drawings into the floor with a knife. His current project was a mountain range. For the moment, this consisted of three identical triangles in a row. Captain C sighed. He would admit, he was no artist, but at least this was more interesting than the same patrol he did an hour ago, and the patrol he would do in another hour, and the hour after that. It was this in this state that he heard a faint knock on his door. He got up to open it, but before he got to it, it creaked open. A woman's face peeked in. She had brilliant green eyes, hair as dark as night, and very defined facial features. "I don't suppose you'd accept the company of lonely little me, would you?" She asked him. There was the faintest hint of a sly smile on her face, which did not escape the attention of Captain C.

"Oh, but of course!" he exclaimed. Please, come in, come in!" The lady merely smiled a bit more coyly, tilted her head, and exposed some of her neck. Captain C walked up to her, extending his hand. "Please, come in," he said in what he hoped was a reassuring voice. The woman's smile suddenly grew much wider, exposing sharp fangs. The door blew open as she charged through. Her right hand went directly for Captain C's throat. She picked him up with one hand, raising him higher and higher. The rest of her body had come through the door, exposing womanly torso, attached to a lengthy, limbless, lower body. She coiled up on the floor. She dropped Captain C, only to catch him, wrapping her lower body around him. He struggled to breath, let alone speak, as his attacker loomed over top of him. She bent her upper body to the floor, picking up the knife which Captain C dropped. The attacker tilted her head back and forth, watching her opponent slowly suffocate, twiddling the knife in her hands, seeming to be indecisive. Finally, she made up her mind, thrusting the knife through the skull of Captain C, before dropping his limp body to the floor.