I'd say that 7 people counts as mass murder, especially when 4 of those murders involved walking round a school with a camera filming yourself killing the kids (and one teacher). I suppose you could define it as 'serial killer' if you really want to go the full grammatical broadside, but I must admit, considering what happened, arguing terminology is a strange route to take.
The guy jumped out of a window firing guns at the Police, I'm not really sure there is a procedure for that as such, you simply take action to defend your own life as best you can, until that point they were trying to negotiate his surrender.
Edit: Also, people have to remember that Al Quaida is kind of like Anonymous in makeup, there aren't forms to fill out or tests to take, and those higher up the chain are most likely completely unaware of your existence, in some ways, it's a mindset as much as an organisation.