You are rin you have the beast inside you, you wanted to die because you were fearful it'd take over you, you asked kakashi to kill you bc u wanted to die by the hand of your love, but he refused... so when kakashi wasn't looking you used a invisible jitsu an u stepped in the way of kakashi's lightning blade..... and it was too late for him to stop it.... Obito had used his chakra to watch all this-