In case anyone else is a crazy person, had no issues getting through security for G gates around 1030pm for a flight with a 540am departure from a different terminal.
However now that my friend is gone and I still have 2 hrs to kill before Admirals Club opens I’m questioning lots of life decisions.
Terminal 3 has some very big and long (but slow) treadmills that you can use to pass the time in the middle of the night.
I don’t remember if the other terminals have them as well.