How was smith able to get out of the matrix and into banes body?

I can only speculate, but here goes nothing:

Smith is not an agent of the system any more, so he's not connected 或者 bound to the Matrix. Because of this, the rules of the Matrix no longer apply to him, very similar to Neo's "anomaly" status, which I think makes Smith an anomaly himself in order to balance the equation.

So, with this new freedom, he gains the ability to copy himself. Taking over Bane, which I assume is a lot like overriding his mind like a computer, he travels back into Bane's body in the real world. Does that make sense?