If anything, it does confirm some sort of war going on and the person holding the gun at The Doctor has been fighting the war for a very long time. There's sympathy in The Doctor's eyes and a clear reflection that someone else has been at war before. The Doctor, slowly, takes out the psychic paper and shows that to the other. The Doctor isn't afraid even if he can tell that someone is a good shooter. If anything, his face seems to be up the challenge of staring down the bottom of a barrel.