The Doctor and Amy must find the Cyber control center and stop the Cybermen from converting all the people on Earth. This page may contain spoilers
Below is a guide for the level.
Keep walking through the tunnels, you’ll have to be patient making sure the Cyber Slaves don’t see you.
There are gaps that you can hide in whilst the Cyber Slaves walk past.
When you come to the ladder, walk down it.
When you get to the Cyber Base walk over to the lift area.
The Doctor activates the lift for Amy.
Follow the path around and activate the first lift control you come across. As the Doctor, go and activate the same lift control.
Amy gets captured by the Cyber Slaves.
Run to the broken lift. Get on it and use the Sonic Screwdriver to activate the controls.
The controls on the top level activate a bridge that the Doctor can walk across.
Use the Sonic Screwdriver to fix the lift. This will lead you to Cyber Control
You learn that the professor has been working for the Cybermen and Amy is in the Cyber-conversion chamber
Re-program the Nanobots
The Cyber-conversion chamber is fairly easy to find, you just need to avoid the Cybermen in the same way you avoided the Cyber Slaves in Act 2
Use the Sonic Screwdriver to free Amy
You’ll need to use the Cyber-conversion tools to escape
When you’ve escaped from the Cyber-conversion chamber, watch out for the Cyberman outside
Follow the route back to the Cyber control center
You will need to send the Cyberman back into Cryo-Sleep.
You need to get out of the base before it explodes.