Ending killed this movie

I like twists just as much as the next guy but this takes the cake...

I actually watched this movie because I knew Jason and Jet were opposites and actually because Jet was the bad guy and I've never seen him bested in any movie previously unless I'm mistaken (kind of like Bruce lee has never been beaten). So I was intrigued to watch this on that one fact alone and all the while thinking somehow he'd change sides or not be the actual bad guy and this and that.

I never thought the twists would end up as they did and I must admit I'm in no way impressed and it brought an otherwise 7/10 movie down to a 4 or 5... Not because I'm a big Jason fan or anything but just because it seemed stupid

Seriously if Jason was the cause of Lone's family's death, then he'd do himself in, not take it upon himself to go after the guy who "went a little too far" give me a break... What a weak story ark...