Furlough.
Taking leave without permission is commonly referred to as "unauthorized absence" or "absent without leave (AWOL)." It is a violation of workplace or military policies and can result in disciplinary action.
Yes
A military scientist
It was rumored that he will leave in October 1st, probably earlier or later, they haven't confirmed when he will leave.
DD214
Category III - Military leave/PCS house hunting: MIlitary personnel in an ordinary, reenlistment or convalescent leave status.
Complete your time of service to your country.
A soldier
They did (and still do) call those guys civilians.
with orders and a military ID you will be fine. It is suggested you have a passport (for leave) but you can even travel back to the states with your leave paperwork and your mil id.
Veterans.
He left the military in 2006