Spocklar wasn't following the line of thinking that Sharley was--it never occurred to him that he might actually revert to the Fathers' programming or something that would cause him to like killing. He just knew that he wanted to. Nero needed to die, even the Other agreed with him. He also didn't really notice Azarael, or at least not consciously--he registered staring eyes, but it was regarded as irrelevant because Sharley was more important.
He started to smile just a little. "I'll come back, and I'll be okay. Nero can't hurt me, or.. it won't last if he does." Then he paused and smiled a little more. "I'll bring back the stabby-stick, that's how you'll know I'm done."
Looking down at Marty, he squeezed her shoulder with his free hand. "I'll make sure I don't."