Under the wing - they were discussing the proximity of the AAA they had seen (if it's under the wing then, at the height they were at, they knew it would have been within 1/4 mile).
One of my old friends flew GR1s in these attacks. His first thoughts on the way in were 'why have they left their strobe lights on?' - before long, though, he realized that the lights were the muzzle flashes of the AAA.