Yes - “Charlie is in the wire”!
A quote from a movie, but I don’t remember which one. One of those war movies though. It meant that NVA or Chinese had breached the outer perimeter defenses.
Better: 'Charlie don't surf'.
https://www.youtube.com/watch?v=uU9Y1sNs1rs
They used to describe the Viet Cong with military phonetic alphabet as Victor Charlie, so I always thought Charlie was the North Vietnamese.