You really can't choose what tool you're going to use if or when the time comes. Only thing you can do is be trained or skilled enough to do what is needed at that time. This case was more of a perimeter control situation. The officer opted to increase the magnification which is fine. Iron sights have been used at that distance or greater as in the North Hollywood shootout. Use what you got. I'm glad the kid and the officers made it out fine. A lot of trauma to that poor child.
@Gingerman and @Gohring65 both of you need to cut the shit or the bans will start. Second post where this is happening. If one of you sees the other then cross the street and don't engage.