Can anybody explain to me why the TARDIS didnt go into the void when the Cybermen and Daleks did?
If it was somehow able to withstand the pull of the void, why didnt he just tell Rose to go and wait in it where it was safe?
The tardis did not go into the void because it was locked to specific coordinates in the universe, or a certain point in space. It will not move from the point without being physically lifted, or being driven by a Timelord ( I.E. The Doctor, the Master, River Song, ect.) This is true even when the planet is removed. (as shown in The Stolen Earth)
As for Rose, I assume he knew that she would have been too stubborn to just go to the Tardis and wait when she could have been doing something to SAVE THE WORLD from the Cybermen and Daleks.
I was under the impression that the TARDIS doesn't really exist in normal time and space. That is was more like a door way that opens in a certain spot with the smaller physical representation of the police box being the only part of the TARDIS that is actually there while the rest of it exists elsewhere (hence why it is bigger on the inside). That would be why it didn't get sucked in.
As far as Rose going to the TARDIS I tend to agree with the previous poster that Rose probably would not have gone also there is a question of time. Would she have had the time to go there and get in it before all hell broke lose?