We all need to be able to go into condition white. We need to feel safe, and to be able to relax, rest, and recover. Being in a constant state of condition yellow or red, will lead to exhaustion, and psychiatric break. Most vets returning from Iraq and Afghanistan are constantly in a state of condition yellow, of high alert, and many are stuck in condition red.
In previous wars, our returning troops would be put on a ship for up to thirty days as they returned from the battle field. They were given time to decompress - to share their stories with other veterans who had been there. In most cases now, a returning vet will be home in less than a week. A typical story I hear is they went to tell their girl friend or their buddy about some of the things they had seen. Their friend went white and said they couldn't handle listening to their story. After that they clam up, and won't talk about it at all. One of the best ways to get over a critical incident is to tell your story to a safe person that can handle hearing it. Talking it out will take away some of the power the incident has over you.
Chaplains generally see a lot of tragic death, and horrible calls. They are a safe person who has seen and experienced enough death and atrocities that they can handle hearing your stories without being damaged. The chaplain is also the best person to talk to about how your faith has changed. They are able to offer confidentiality, an understanding ear, and professionalism.
LEOs returning to patrol after being deployed need to know they are OK. They are part of a bigger family, and they need to share their story. Encourage them to talk when they are ready, and don't shut them down when they do talk. You may be the lifeline they need in order to continue their meaningful career in law enforcement.