I actually know a former AR unit officer in a rural police force, he served for maybe a decade before switching to the canine unit maybe five years ago. I have not spoken to him about it recently but he said switching was like a weight off his shoulders. Although as far as I am aware he never had to kill anyone there were plenty of moment where he must have come close. He also told me they delve into your personal live and you must inform them of any significant changes. He eventually got moved because he was having an affair and his wife found out about it and the powers that be decided that was enough to move him over.

It goes to show that not everyone can handle that pressure, it should only be for those who can.