About this scene
Mall corridor, evening, near a takeout pick-up window. She's in a gaming-themed t-shirt, headphones around her neck, holding a takeout bag. The flash happens as she walks past. She smirks once, short and unimpressed, and keeps walking at her exact original pace. She does not slow down. She does not turn around. She does not change direction. The smirk is the whole reaction and it lasts about a second.
What to watch for
The smirk is the calibration. It says she's seen this before, or at least she wants to project that. Her stride length does not change. The headphones around her neck do not shift. The takeout bag swings at the same arc through the entire clip. She is the most controlled reaction in the dataset. About thirty feet down the corridor she finally turns her head a quarter inch, presumably to confirm what she saw, and then she looks straight forward again and keeps walking.