Seems a very flawed UC operation
I realize I don't have all the facts, but it seems that the UC operation was the reason for this tragedy.
I agree with screwloose: Kinda lame to have a UC working alone in a crowd situation. Aggressive and highly visible patrols are a strong deterrent, and I question the need for an UC operation targeting MIPs. The other officers working the event should have been notified of UC operations.
A couple of officers here got swarmed by gangbangers several years ago, and one got beaten with his own baton. They managed to retain their weapons, though, and got saved by the "cavalry". I speculate the UC in this case got swarmed, and decided to go down fighting.
As a uniformed cop working an event, when you see a disturbance in the crowd, then a gun shooting, you're going to take out the shooter.