To be honest, I'm somewhat more unnerved when a Police Officer is killed by a criminal than when someone is killed in Iraq or Afghanistan.
The Marine, Soldier, Sailor, Airman, or Guardsman knew they were joining during a war, and if any of them didn't think that they would end up in the sandbox, they are, simply put, ignorant. We all know the dangers of war, and we all made a conscious decision to voluntarily serve despite the dangers.
A police officer, on the other hand, shouldn't have to wake up and worry if someone will shoot at him when he goes to work.
My prayers go out to his family. I just hope his death wasn't in vain.