In my opinion, the story of how this event transpired is best told at this point by the media and subsequent official inquiries. I know I wouldn't want to hear any radio traffic of the incident myself.
I understand what you're looking for, but I don't think that any speculation by scanner listeners on what they heard or what they think happened will serve any beneficial purpose for now.
What's more, other discussion groups have brought up the point that some media outlets are trying to twist this story around to the point where the shooter was said to have used his 'police scanner' to lie in wait for the members. I don't know about anyone else, but I don't feel the need to fuel that particular fire myself.