Overlooking that a lot of the people they shoot/kill aren't "innocent" -- it's more a matter of excessive force (such as shooting an unarmed suspect) -- they only keep their jobs when a panel or IA rules that it was a reasonable use of force.
At any rate, if you want REAL job security, join a teacher's union. You can no-show or just sit there reading a paper instead of teaching and still keep your job. That's REAL job security.
I think the cops who shoot and kill innocent people should lose their jobs. ---