You can't help being proud of how he relies on you in times of trouble. He takes you with him as he chases criminals and psychopaths around London and the rest of England; you make him feel safer and braver, and that's exactly what you're there for.
You love the touch of his hands – strong, steady hands that are far more skilled than anyone would suspect. He's an army doctor after all, he knows how to kill people as well as heal them.
You never regret it when the gunshot echoes in the distance, and another one bites the dust.