Palm trap and punch

The prompt

Tight two-shot in profile on a city rooftop at dusk, an older Wing Chun teacher with silver hair and a young male student in black kung fu jackets trade a fast trapping exchange, cinematic, real time dropping into slow motion on the punch. 0–2s: they face each other at close range, forearms touching, the city glowing behind. 2–4s: she slaps his lead arm down with her open palm. 4–6s: in slow motion she fires a short vertical-fist punch that stops just short of his chest, his jacket fluttering. 6–8s: back at real speed they both return to the start, forearms touching. Throughout: both figures visible from the waist up, laundry lines and apartment windows blurred behind, cool blue dusk with warm window light.