The Cybermens' plan in this story is remarkable. Most alien races intent on taking over a space station would usually form an army, attack the base (especially when they clearly outflank the station in technology and strength, which the Cybermen clearly are), mop up the survivors, put up some new wallpaper, and take control.
But not these Cybermen. First, they create a supernova to fling meteorites across space (if you're starting your plan with something as complex as engineering a supernova, you know you've got your work cut out for you). The meteorites are headed towards the Wheel, so, naturally, the station will have to defend itself with its laser gun. What does the laser gun need for power? Bernalium. So, the Cybermen somehow smuggle some Cybermats aboard to discreetly destroy the Wheel's bernalium stocks. But, lo! There is some more bernalium on board a mysterious rocket which is floating towards the Wheel. So, the Cybermen (all two of them) hide in a crate of bernalium in the rocket, the same rocket that, were it not for Jamie's sabotage of the laser gun in Episode Two, would have been blasted out of the sky before the Cyberman plan even got off the ground.
Mental. The Cyberplanner is clearly doing its best to earn its paycheque. Future Cyber-invasions would dispense with the middle man, though. Pity, that, because despite the over complexity of the plan, the Cyberplanner doesn't half try.