Since Gungnir needed to lock onto something in order to be thrown accurately, there was a single place perfect for this occasion.
Usually, one would target a certain mana signal but Shiro chose a place that lacked any sort of signal in a world flooded with mana.
She chose the null mana zone.
A place of her own making. It was the perfect target in order to not harm anyone as the resulting impact would only be absorbed by the zone with the mana being funnelled towards the repairs of the area.
Flickering through the cycles while catching up to her spear, Shiro could see the destruction that Anima had started in each cycle. Each world had its own problems and Anima simply amplified the destruction caused by it.
Since this was the result of their battle, Shiro felt obligated to at least try relieving their pressure. Snapping her fingers, she created a holographic projection of herself and sent it towards each of the cycles.