The average speed of a Moscow Metro train is about 40 kilometers per hour. The maximum speed on the longest stretches is 80 kilometers per hour.
If we imagine the train racing at maximum speed the whole way, it would take less than an hour to reach Podolsk. To the southern border of the Moscow Region — just over an hour; the distance from Kolomenskaya metro station is roughly a hundred kilometers.
Assuming the train ran for six hours, it could theoretically end up in places called Svapskiye Dvory, Fatezh, or Malaya Umrikhina.