It won't happen and/or would be bad writing anyway, because...
-She's too far away to get there in time. Kakashi wouldn't allow her to go, anyway.
-She wouldn't lay a hand on Sasuke. It would be more likely that she'd attempt to hug him than kill him. (Yes, I'm serious.)
-Even in Sasuke's weakened state, his speed still outclasses her. She can't land a hit if she tried.
-Sakura's not exactly the stealthiest shinobi anyway. Sasuke would notice her coming and take her out early on.
-Sakura is the 12th most popular in the series. Sasuke is the 2nd most popular after Naruto. Kishimoto isn't messing with the fandom to that degree. He likes his money.
-Sasuke is Kishi's fave character to draw, Sakura isn't even on his radar. Kishimoto likes Sasuke very much, he's not going to humiliate him with a character he doesn't care much for.
-Sakura woke up wondering about Sasuke first. She has more concern for him than she does Naruto. She wouldn't save Naruto in a fashion that would physically hurt Sasuke.
tl;dr= It's not happening. If it did, it would be bs. Plain and simple. U_U