Cold War: Promotional Images

The BBC have today released Promotional images from up coming Zygon episode, Cold War.

The First one up is an amazing image of the Doctor and Clara, Clara of course very wet and cold, and The Doctor looking very smart as always.

The Doctor preparing for the Zygon's arrival??

Why's the Doctor's Sonic glowing red and not green???

A chained up Zygon awakes...

So what's a Zygon doing on a submarine, chained up? Why's the Doctors Sonic glowing Red, and will Clara realize just how dangerous being with the Doctor really is?

Doctor Who - Cold War - BBC One & BBC One HD - Saturday - 6pm