She's too quick to kill. When a yukkuri attacks, you just don't kill it right now, you make it regret its attack by making it suffer a LOT. Always go for a very slow kill in case of attacks. If possible, kill it last, kill its entire family before its eyes, when at the same time telling it that it's its fault for attacking you. Then you make it suffer for the longest possible time, while telling it that everything that has happened is its entire fault. Even if the attack is justified (she killed one of them first).