Lord Grievous said:

Personally I think it would be a little too convenient for Luke's hand/lightsaber to be falling down the same shaft he does, not to mention at about the same time even though there must've been at least a minute between it being cut off and Luke jumping.

Then again, if the outer door hadn't opened in between, they would have both fallen out at the same time. We don't know how often the thing takes a dump ;)

I think this is a perfect opportunity for Adywan's hand to make another cameo.

Adywan's hand could be the new Wilhelm, showing up at least once in each film! Or even worse... kind of follow the action around like the fake hand in the beginning of Mystery Men...