You say “Char!” and you hear a click as the door opens. You succeed! Then the Doctor materializes next to you and says “What did I miss?” You cheekily say “I’ll tell you later.” and you both break into a run for the final chamber. But to little avail.
Reaching the chamber first, Scarman destroyed the Eye before falling to the floor and decaying to dust.
You may be late, but the Doctor realizes that the loss of the imprisoning force will not be felt on Earth for two minutes, that being the time that radio signals take to travel from the pyramid on Mars to the prison chamber in Egypt, and you both dash back to the TARDIS to return to the mansion.
Sutekh begins his victory journey through the time tunnel; at the same time the Doctor removes a module from the TARDIS and attaches it to the other end of the tunnel springing a “temporal trap,”
immobilizing Sutekh in the timestream, and instead forcing him to a point 10,000 years in the future, aging him to death. You and the Doctor leave in the TARDIS as the mansion is consumed in flames. You have won! Game over.