The Tardis it turns out has a telepathic translating function which conveniently explains how the Doctor and Rose can communicate wherever they go. Another nice touch: the Doctor is a bit cold-blooded. "Everything has it's time and everything dies," is what he tells Rose as he stands by and lets the last human explode. We also learn that Gallifrey was destroyed in a war and the Doctor is the last of the Time Lords ... a decided break in the continuity quite obviously ripe with time travel paradoxes. Not sure that was a good idea but we'll see how much impact it has going forward.
The next ep will be set in 1860 and apparently involves Charles Dickens and some sort of zombie-ghoulie. Looks more than a little like "Talons of Weng-Chiang." I'm digging the scene.