Greg decision
I think he is unwise to go back to the rangers since it would be a death sentence but i guess he feels more fufilled doing that than being a civilian tech.
He doesn't need to be a tech only.
With his skillset he could do intrusion checks and other things of IT consulting and with the police as reference, he could get as interesting jobs as the other cops do with private security.
I doubt he is depicted as bored. He was rather played pressured and with some sort of anxiety. Going back isn't giving him more purpose. Its just going to kill him.