Seven 2 One

Seven 2 One (simplified Chinese: 关人7事; traditional Chinese: 關人7事 is an 2009 Hong Kong crime drama film directed by Danny Pang.
Plot
Convenience store clerks Chrissie (Chrissie Chau) and Katy (Katy Kung) decide to get back at their sleazy manager Leo (Leo Chim) by having their friends pose as robbers and hold up the store, but events escalate out of control into murder. What started as an elaborate prank sets off a butterfly effect of crime, consequence, and desperation as more and more people get pulled into the mess.
Cast

Elanne Kong as Ling
Pakho Chow as Pak-ho
William Chan as William
Stephanie Cheng
Siu Fay
James Ho
Gary Chiu as Gary
Chrissie Chau as Chrissie
Izz Tsu
Wylie Chiu as Wylie
Jones Xu as Cheng-hei
Katy Kung as Katy
Chan Chor-kiu as Carolyn
Yung Cheng as Yung
Leo Chim as Leo
Terence Chui
...