Rod knocks kunai out of Sakura's hand, Obito is incapacitated by black zetsu so Sakura uses her remaining chakra to defend herself, failing and Madara takes the Rinnegan and the final battle truly begins. Sakura manages to escape either by Sasuke suddenly knowing kamui or Naruto doing something illogical to the NV and enters kamui.
Other scenario, Madara kills both Obito and Sakura and returns to the battle with their bodies to gloat, gains the Rinnegan and will be decimated by a grieving/enraged Sasuke and Naruto.