A wide-area spell placed below the ball's breakup point to catch falling allies and give them a moment to regroup.
When the ball broke apart over Larracos and all of the allies began falling deeper into the city, the plan accounted for it. Just below where the ball had stopped was a wide-area spell called Bounce House, waiting to catch them all and give them a moment to recover while they received instructions.
While the enemies floated upward toward Princess Donut's Astral Paw, the allies caught by Bounce House and the NPCs and remaining troops were to storm The Castle, now drained of acid, with the understanding that the remaining defensive towers would keep firing until someone set foot in the Throne Room, at which point all towers would go inert.
The safety net for allied forces during the ball's breakup, enabling the ground assault on the castle.