Gotta be a glitch. You had no assists and only 4 kills when the "5 kill streak" popped up. It had to have something to do with the self rez on the lock or your super. Everything else was a relatively straight forward kill, although you probably shouldn't have even started it to begin with. That lock had you dead to rights in the beginning. Then again, he did feed you two kills so I'm thinking he was just bad.