Factual error: During every outdoor scene in Antarctica, heavy blizzards are shown raging constantly. In reality, such blizzards are extremely rare at the South Pole, thanks to the almost total absence of precipitation Antarctica is effectively a desert, as the air is very dry: with very little moisture in the air, rain or snow is almost impossible.
Factual error: In the first close-up view of Mondas, the planet is spinning rapidly so that we can see that its continents are identical to Earth's. But this would mean that Mondas is spinning on its axis once every few seconds - tens of thousand of times faster than Earth. This would be such a fast rotation that the planet would not be able to hold together under the centrifugal force.
Factual error: In Episode 3, Zarof fires a gun. The muzzle is seen and a sound is heard but the gun doesn't move and there's no smoke or bullet, no flash or anything at all. (00:23:05)
Answer: TARDISes are generally available for properly authorised use on Gallifrey; they're not usually assigned to a particular Timelord on a long-term basis. The Doctor stole his when he left his homeworld.
Tailkinker ★