When I first joined the Police if you attended horrific stuff we got pissed afterwards. Later we had to attend a meeting with a Psych, it was compulsory and it showed the Police moving in a positive direction. Before that there was a 'harden up' attitude from bosses.
Most Police stress is caused in the Stations, not on the street.
You would not believe the bullshit Cops get put through by their Administration. They are great at inventing more forms. I used to shit myself when one of them had a god idea.
I can categorically tell you they do not protect their own, a lot will believe those making complaints. Often staff are saved by notebook entries and such like. The best I heard was some Cop belted some prick in Auckland who desperately deserved it When interviewed the only witness, an old chap, said, 'I agree with everything the young Constable said' When told he didn't know what he said the old guy said 'I don't care, I agree with everything the young Constable said'