Oh, I know. I read that the actors were almost embarrassed shooting the whole thing. That is was that obvious just how bad that scene was.
1) Ang is not the world's most articulate person when he's speaking, at least in English, at least in interviews. Sometimes his descriptions of the plot of BBM seem almost ... oversimplified. So it's possible that a commentary would be disappointing because his actual work as a director is much more nuanced than he would describe it, speaking.
You might want to look at the essay he wrote in Crouching Tiger, Hidden Dragon: Portrait of a Film. He wrote about his personal spiritual beliefs and how they contributed to the movie...about the Tao te Ching, etc. He is more articulate on paper than speaking in English. Probably he was well edited!