Obito did not use powers to save himself from rocks

[Honord Sage]

A last act of desperation on Obito part to survive, His sub conscience activated is dimensional tech and He fell away from the rock minus His right arm.

 

[saltal]

B. Obito spontaneously activated his MS with an imperfect Sharingan and used Kamui to escape the cave in and proceeded to warp to Madara's Lair.

Both are incredibly unlikely, in my opinion, but it is what it is. And given the almost direct reference to Obito's powers, I'm going with B. We'll probably never know either way, but hey, Kishi does what Kishi does.

I think that is obvious, given another hint - Obito says that Madara was his "anscetor". It makes sense to infer that their eye powers are therefore at least partly related. It would have been impossible for the injured Madara to escape on his own after the fight with Hashirama. It's possible he managed to time warp to that place using his MS. Given that Obito is a descendent, they may have shared the ST location, which is how they both end up in the same place.

 

[narutoblitz]

Madara used Kamui to save him. He never told Obito about it, and during their fight I'm guessing he uses this fact to gain the upper hand and kill poor Obito heh

 

[JakeLife510]

Throughout the series Obito has been using his 3 tomoe sharingan to phase through things, not MS.
Even though he has it awakened he was using space time while 3 tomoe sharingan was there

So he could've used his space time tech on accident