Why exactly did Wah Sing Ku kill the guy on the roof?
I don't see in what way he betrayed him.
shareIf I had to guess I'd say he probably wasn't happy the guy couldn't control the crew they opened fire just off the US coast stupid thing to do if they had to kill someone they should've done it at sea. Then the fact the police have made him makes him a liability the police will continue to look for him and possibly get him to talk better to kill him than risk it.
also Ku seemed to kill everyone once they'd done their part remember the passport guy who was pushed into oncoming train then he killed uncle benny and the artist who made fake money.