Sasuke would need to have a teleportation jutsu to do that.
And I agree with most of you, it's obvious Obito will save Sakura, probably just by pushing her at the beginning of next chapter. If something big was supposed to happen, like Sakura being hurt by Madara's shot, it would have happen at the end of this chapter, and that would have been the cliffhanger. Her not having been hurt in this chapter, makes me think she won't be in the next one.
I think the focus of the next chapter will be a confrontation between Obito and Madara, maybe with Sakura's help for Obito.
I agree
1) There's no evidence that Sasuke even saw Madara jump there
2) It makes narrative sense for Obito to save Sakura by sending her out of the kamui dimension- he couldn't save Rin, but he does Sakura, giving him a bit of emotional closure on that trauma
3)Obito needs to have his final confrontation scene with Madara. This gives him that chance.
4) It brings Sakura back to the main point of action