the E.T.A. evening montage
Michael Pemulis is gently raising one of the panels in the drop-ceiling and shifting it on its aluminum strut, the panel, changing its lie on the strut from square-shaped to diamond-shaped, being careful not to let it fall.
Context
A throwaway montage-panel that is pure concealment-craft. Pemulis works a drop-ceiling tile off its strut and resets it "from square-shaped to diamond-shaped" — either stowing/retrieving a cache in the standard E.T.A. hiding-place above the panels or leaving the tile deliberately mis-set as a covert tell (a has-this-been-disturbed marker). Read either way it is the amateur wing of the book's tradecraft: the same instinct that hides warheads in ball-buckets (073) and contraband in a hat-lining (050), practiced by the Academy's own resident counter-surveillant. (The cache/marker reading is inference; the raw shows only the panel being carefully re-angled.)