As soon as you play as Li Ying (the obligatory Chinese girl character in modern action movies), you can use her slow motion skill by pressing
. This depletes your energy (orange) meter. Wait for energy to fully replenish, and repeat the process until the achievement pops.
You can do this right when the chapter begins, without any enemies nearby.
If you somehow miss this during your playthrough, use the Chapter Select option to select the level "Chinatown".