Sorry,
Esquilax, but I do not grasp your logic.
You say that if we take out zhang manxing, there still will be two fighters left, and those are dangerous. Right. But if we take on those fighters, then it would be zhand manxing who will be left in the game. The reason why I want to take him out was stated already - I suspect that the man will employ an underhanded tactic we might not see coming. The man already deals with drugs, why not poisons?
Furthermore, you dismiss the girl as a fighter, but you never ask yourself - if she is a lousy fighter,
why is she here? What for? If you know her master is a ruthless bastard with not a grain of conscience left in him, you have to suspect the worst. She is really easy to ignore due to how out of place she seems, but would that really be wise?
Next, you talk about the alliance, and how taking manxing out would spell our doom... why exactly? If we take him down, the brothers will pile on Wuni, and we will only be left face-to-face with the bandit. There will be no alliance anymore, everyone will be left to their own devices. I can't see it as a bad thing.
If you take one of the brothers out, however, there would still be 3 or 4 fighters aiming at your throat. It improves Wuni's chances, sure, but it does not help
your chances any - and you are in a far greater danger than he is.
Besides, seeing how the monk and the beggar do not like dogpiling, one of them may provide support to Wuni and take on one of the brothers just to make things fair.
Forget about Wuni for a second, you can not hope to watch his back and yours simultaneously with just one eye. Once Yunzi came into picture, other ways of achieving our goal became available. You can get her to win the tournament and still marry Rinchen to Wuni afterwards.
I want to get rid of zhang because I see him as the biggest threat that currently has his eyes on you. The bandit is predictable, the brothers are predictable, but he is not. I do not want to leave him for later.