Ok, I thought that was it. So why the fuck did the other guy die? Why did Chinaman shoot him? I thought they were gonna pull down each others pants and jerk off.

The Brit dude from Crank? Well, appearently he was really the dirty agent and was in it with the Yakuza (though, you would have never have known this since the movie doesn't even allude to him being dirty until the end). But he feels bad for his friend dieing (since he knew about the Yakuza plot to hurt him) and always thought it was the real rogue that did this.
There was a sniper stationed there to kill Rogue but when the Brit dude found out it was really his friend, he blocks the bullet with his body! (as you saw). Then he dies and thats it. It was one of the worse endings ever.