Alex walks towards the beach huts to get his raft, stepping between reclining sunbathers. The camera moves with him and halts as the profile of Brody comes into view in the foreground, dominating the right side of the frame. The concentrated stillness of the chief's gaze sets him apart from the rest of the people of the beach, and his right hand is held to his mouth in a typical gesture of deep thought. His posture can also be read as an emblem of his complicity in the cover-up of the first attack: forbidden to speak, he is, at least, determined to be on the lookout for any further threat.
The scene is as much about Brody being watched as it is about him watching. Shots alternate between what he sees and his reactions to it in a textbook example of the Kuleshov effect. As an audience we share with him the knowledge that none of the other participants in the scene have, and so his heightened expressions of dread become ours. In a sense, we are watching our own reactions up on the screen.
Throughout much of the movie, Brody is placed in the position of observer. At key moments he directs his gaze out towards the ocean, and - particularly in the presence of Hooper - he is relegated to the role of onlooker, first as the fish expert delivers medical analysis in the morgue scene, then fillets the tiger shark in a 'half-assed autopsy', and later explores Ben Gardner's half-submerged boat.
Brody sits in his chair throughout almost the entire scene: what, after all, could be more emblematic of an observer than a seated posture? Even when there is an appearance of a threat, Brody does nothing more drastic than half-rise to a crouching position, and when his view is blocked he simply shifts his beach chair a few inches in irritation. Even at the moment of the attack, he remains rooted to the spot - it is the camera and indeed the image that react with movement.
