The Doctor makes a confused face at the word 'Trooper'and The Doctor is about to either grab the other to take to the Tardis or go up and join him. However, it's too late and The StormTroopers arrive and The Doctor puts his hands up.

When asked to identify himself, The Doctor takes out his psychic paper and they read that he's a commander and ask what are you doing out of uniform?

"Camoflaguing with the locals. Now! There's more important business to attend to back at the base. I'll take care of this and you get back, are we clear?"