1) The Tardis went to the other parallel earth as well. Why didn't it get sucked into the void too?
2) The Black Dalek time shifted, thus avoiding the void (so to say). Obviously, he'll be back. Anyone remember his name?
3) Any Cybermen made on our Earth (I'm looking at you, Yvonne) would not have been sucked through the void.
Intriguing thoughts and/or plot-bunnies.