It has been previously stated that weapons do not work in the tardis but the Cybermen weapons do in this episode.
As the freighter approaches Earth after coming out of the Time Warp, the continents look very much like they do in the Present Day. 65 million years ago, Korea and Japan would not have been in the positions that they are seen in.
As the freighter travels back in time The Doctor tells the cyber leader that it is still locked onto Earth,s co ordinance, however the earth is continually moving , it continually orbiting the sun, the Earth moves with the solar system around the Milky Way Galaxy which itself moves through the Universe, so the co ordinance of Earth will have changed quite substantially over 160 Million years so the freighter would miss the Earth by a long way.
The crashing freighter seems to be heading for current-day Korea. But it has been established that the meteor crash that caused the mass extinction at the end of the Mesozoicum, landed in Yucatan, Mexico.
The two soldiers are killing the Cybermen with the Cybermen's own weapons. One complains they are running out of power and they retreat. Yet they are surrounded by fresh weapons from the dead Cybermen they have just killed.
Surely one of the doctor, Nyssa or Tegen should have remembered about the second Cybermen in the tardis.