http://news.bbc.co.uk/2/hi/europe/3636196.stm
Read more about the report here and they even have video shot by the hostage takers.
Apparently the authority was hoping for a peaceful resolution but things took the wrong turn and they were forced to act when the hostage takers began shooting at the hostages.
The theatre case was also in Russia, Moscow. The militants then was also armed with explosive thus by gasing them is the most appropiate solution rather than storming into the building and facing a certain death to the storming forces and hostages. the gas was supposed to rendered the people in the theatre unconcious before they forces moved in. However, they overestimated the amount of gas pumped into the theatre which not only kill the militants but also most of the hostage.
Sad sad sad.......Misguided ideals........