About this scene
Mall food court, mid-afternoon, three girls sharing a table near the central walkway. He walks past the open side of their table. The first girl laughs out loud, immediate and sharp. The second one catches up two seconds later. The third one is the slowest to register, and she figures it out by reading the other two faces before turning to look. All three reactions happen inside four seconds, and they are still laughing about it ninety seconds later.
What to watch for
The reaction sequence is staggered in a way that makes the clip work. Girl one is direct. Girl two is reactive. Girl three is social. Watch the chain of laughter spread along the table. The food gets neglected almost immediately. None of them eats for the next ninety seconds. The third girl is the one who eventually turns her chair to face the corridor where he was, and she stays in that position for the rest of the clip.