Way Cool Idea I have, maybe I am more creative than the writers.

How about instead of being generic evil Tong Po has a twisted ideology?

He respected Erik and in the preview told Kurt "your brother was brave he was a warrior". I saw him PRAYING in the preview, and this establishes that he is religious.

How about he IS obeying the metaphorical "golden rule" because if he ever loses what he wants is to be killed because to him dying in battle is the greatest honor. He obviously does not kill Kurt when he disarms him during the scene where Kurt goes after him with a gun. My guess is he will not think him worthy of it.

Maybe he only kills an opponent who puts up a good fight because he believes if you die in battle you go straight to heaven or something, so maybe in his warped mind killing an opponent is a REWARD and if he beats you too easily he does not think you are worthy of going straight to heaven so he lets you live.

Have Kurt planning to avenge his brother by killing Tong Po but at the end when he finally defeats Tong Po he is about to finish Tong Po off and he notices a smile on Tong Po's face, maybe a weak smile since he has been badly beaten up but a happy smile none the less because Tong Po WANTS a warrior's death. He knows that if he loses on purpose it would not be a true warrior's death. The only way he can get the most honorable of deaths that will lead straight to heaven (in his warped religious mind, look at Muslim terrorists religious people are crazy) is to fight as hard as he can but lose anyway.

So he is finally getting what he has given so many others and in his mind he feels it is "his turn" and he is HAPPY ABOUT IT. An exhausted Kurt realizes the man WANTS to die and so as an ironic act of true revenge changes his plan and walks away victorious and forces Tong Po to live with his defeat and deprives him of the "warrior's death" he wanted so badly.