The doctors reveal why you need differently shaped teeth to eat your food safely - by wearing some very strange gnashers! And they find out what it's like to be lifeguards in Operation Takeover. We catch up with Ouch Patients Kaden and Maisie, and Dr Chris joins the Royal Airforce to find out what it's like to give emergency medical care to patients in the back of a plane which doubles as a mobile military hospital! Meanwhile in accident and emergency one patient arrives after a nasty biking accident, and another has a busted wrist.

Dr Chris and Dr Xand reveal how your brain enables you to learn new things with the help of three human 'samples' from the Cupboard-of-Everything, a giant pile of sand and some water! In Operation Takeover the twins join the fire service and discover how tough it is to rescue people in a fire. Plus Dr Chris heads to the ophthalmology department to find out to treat a lazy eye, and we catch up with Ouch Patients Bolu and Millie. Meanwhile in accident and emergency one patient has dislocated her ankle and another has injured his knee in the playground.