Indeed, this may mean that he has not carried one since World War II, reasoning that if he were caught, he would be able to explain anything he was carrying except a gun. He also believes that guns give their carriers a dangerously false sense of security, and dislikes the noise they make. His resistance to interrogation is exceptional and he has managed to keep the "suffix-nine" designation indicating he is "reliable under torture".
In his choice of self-defence methods, he favours Shotokan karate, much like Trevor himself. Additionally, Quiller has knowledge of Chin Na—a related, complementary art that relies on advanced joint manipulation. He does not carry a firearm "in peacetime".