from todays Washington Post: the first 3 paragraphs of an article based on interview with a doctor who participated.
(underlining mine!)

"The 29-year-old conjoined twins who died this week during surgery had unexpected anatomical connections that virtually guaranteed they would die in a single-stage operation to separate them. But a two- or three-stage operation done over weeks or months might have been successful, the American surgeon who helped lead the operation said yesterday.

However, the twins' instruction -- verging on an ultimatum -- that the single-stage separation surgery should be completed at all costs was honored by the medical team and by the patients' representatives, who were consulted halfway through the operation. That loyalty to the twins' wishes indirectly led to their deaths.

"In this situation, the twins' strong desire to go for broke played a significant role in the outcome," said Benjamin Carson of Johns Hopkins University. He was invited to help lead the operation because he had separated three other sets of head-joined, or craniopagus, twins."


full article here

I guess we can argue all day about what 'should' have been done when the difficulties were encountered....but I agree with the majority who think the wishes of the patients were the important issue.