Awesome theory! It is probably a combination of exactly what you said as well as probably the ability of Kamui in and of itself.
My bet is that while in the Kamui dimension, he is capable of moving/teleporting to new locations, and basically cuts down travel time by a factor of two (takes half the time to get where he's going).
However, due to his half Zetsu body (which would be connected to the regular Zetsu) he could probably teleport himself directly or directly within a radius....such as he did against Danzo....of the beacon!
Awesome work friend!