Whether you use them as visual aids or as references for your own scene setting descriptions, I thought it was important that people visualize the environment the Kowloon battle takes place in. Now imagine those streets crowded by hundreds of drugheads clawing their way past the make-shift barricades the Triad has put up. Consider the dangers of smoke, fire, and enclosed spaces.
The dangers of fire and smoke in that environment are dramatic to say the least. I'd be tempted to give the PCs some incendiary grenades and see if they're foolish enough to use them. If that place went up in flames it would be a massive death trap. The drug addicts would be the least of the PCs worries.
K.