Now that the poison had been injected, the second prisoner's body would steadily numb and become useless, starting with the place she had stabbed him and working it's way outwards as the venom flowed through his blood stream. She didn't use something more lethal because she wanted to take her time with him aftewords. Their retaliation was too slow, as they were probably not used to or expecting a target as quick as she was. She nimbly leaped forward, passing over their legs and ending up behind them as she swung another set of claws at the first prisoner, poised to carve up his back.