Danny Pink
From Tardis Wiki, the free Doctor Who reference
Danny Pink was a teacher at Coal Hill School, where he taught mathematics. He had previously been a soldier, and established the Coal Hill Cadet Squad at the school.
A pupil once asked if he had killed anyone, including both other soldiers, and also civilians. Although he refused to answer, he visibly became distressed.
He was introduced to Clara Oswald by Mr Armitage. She later asked him to join her for a drink and he embarrassed himself. He later went out to coffee with her. (TV: Into the Dalek)