Indifference is the sign of being "burnt out" in a job. DC spent too much time doing the same activities day after day, year after year, decade after decade. This condition affects policemen, doctors, teachers. But it was up to DC bosses to change his tasks within police force, especially when he started showing aggression. I think it is a good idea for police officers to have some form of therapy or just psychological session every now and then to deal with constant stress in their job which leads to indifference and the feeling of being burnt out.