doubleofive said:
Or what happens to the rock in the next shot when he's rolling out of it.

I've wondered that as well.

Wait, what if R2 is actually has Force powers? That means he moved the rock in front of him. Then he Force Pushed it out of the frame. I knew it. The Force is strong with this one.

LOL. That would be funny. I can see George Lucas talking about it right now. "I've always felt that R2 never has that big of a role. Due to the budget and limited effects, I could never fulfill that vision. But thanks to today's technology, I can now give R2 the role I've always wanted. I can now have a lightsaber fight between R2 and the Jawas, he can finally fly a Snowspeeder and fight the AT-ATs, R2 will use his rocket boosters on the Sail Barge instead of falling of the edge."