When you start to travel in time and space, strange anomalies can occur. Imagine now, dear reader, a Dalek fleet fleeing the Morvellan plague virus. Finally settling on a hostile jungle planet, they start to rebuild, growing in numbers and installing the most senior in a large static Emperor machine.
They are discovered and attacked by a strange humanoid creature who infects the drone's computers with a virus, making the Dalek creature react similarly to a human child. Fortunately the Black Daleks and Emperor are unaffected and after a brief struggle, order is restored. http://www.youtube.com/watch?v=URlwEkaFj7k
Damage has been done, the lasting effect of the virus is a change in perception, a dormant race memory of the presence of limbs has been awoken, the old travel machines feel like prisons. The Emperor decides to return to a spaceborn existence. New travel machines are constructed for a space environment based on a Spider-Dalek model. Later improvements include upgraded maglev motive power and a heavier weapons system capable of handling Mechanoids and other new foes.
A new Dalek Empire is formed. Followed by the revolt of its 2nd Conquest Army under General Xenol inspired by Science Dalek Yttral.