[Iscool]

At the distance he was away from the stage area; I doubt that the angle he needed to 'wave' would be very great.

Perhaps 'that' shooter was far closer to the crowd...

[Elsie]

The compass angle to the concert area ranges from about 34° at South LV Boulevard to 52° at Giles Street.

At 45°, the shooters window was almost perpendicular to his average line of firing direction.

He had an approximate 18° subtended angle of target rich environment.