Susan struggles out of the city and into the (very fake) forest, where she meets an attractive athletic man who identifies himself as Alydon of the Thal race. It would seem that the Daleks perception of mutation is a little different to ours. Thankfully, the Thals wear alot of blue eyemakeup and all have blond hair to distinguish them from other humanoids.
After explaining that she needs some anti radiation drugs, he is very willing to supply her with some though warns her to divide it up and keep a secret stash as the myths he has heard about the Daleks tell him they are not to be trusted. Susan finds out that the Thal race is near to starving and is currently searching for new food sources. Alydon and Susan come to an agreement in that she will act as a contact between his race and the Dalek and hope that a trade agreement can take place.
Susan returns to the city and is able to give the companions drugs to cure them as well as speak to the Daleks about the peace agreement. The Daleks agree to allow the Thals to cultivate the land around the city and offer to give them food. (it seems odd that a mechanical civilisation would have stored food, but don’t let that stand in the way of a good sci fi)
After recovering, the Doctor urges everyone not to trust the Daleks and stage a fight so that Susan can destroy a camera which has been filming them in the cell room.
With this new freedom afforded to them, they devise a plan to overcome the Dalek and escape. Any long term Doctor Who fan will wear a wry grin as they watch this plan fall into place. How simple would it be for future doctors to halt a Dalek with the use of a cape to disable their movement, some mud over their eye stalk to blind them and to simply rip the casing apart and pull the creature inside out?
However, this is what they do, and with Ian shoved into the Dalek, he escorts the others through the city and make a break for freedom.
(Of interest, the Thal race is visited a number of times throughout the Doctors Journey. Their progression from a subsistence based existence to a militarised one is one to watch.)