Ran across some interesting data regarding the term “looking glass”. A couple of things:
First: An early warning system— Operation Looking Glass - Wikipedia
https://en.wikipedia.org/wiki/Looking_Glass_(airplane)
Operation Looking Glass.
The AEAO is supported by a battle staff of approximately 20 people, with another dozen responsible for the operation of the aircraft systems.
The name Looking Glass, which is another name for a mirror, was chosen for the Airborne Command Post because the mission operates in parallel with the underground command post at Offutt Air Force Base...snip
2cnd: In Black Ops— A term used to denote the mental and physical threshold to truth—once crossed -there’s no turning back—ie you can’t un-know the truth.
Hearing about the truth, is quite different from going through it and seeing it first hand.
3rd - of course, as Q often posts, and as noted above- a mirror.