@WBYeats,
Quote:Could it be interpreted as the location where the agents talked about the plot was in/inside the compound?
Yes it could, although the context leads us to the other meaning.
A "plot on a compound" is not a very good phrase, although it serves as a useful shorthand. (the word "attack" is missing)
"A plot on his life" is better, because we know from that wording that the plotters mean to kill him.
Btw if the word "plot" is used, as a verb, you know that some criminality is intended.