Rin's Cloak of Doom crumbled all spears with dissolution flow, turned them into motes, and reused that energy by using her Chaos concept's effect to turn them chaotic and ownerless.
She was using that energy, forcefully converting it into soul energy with a Soul Vice—> If she destroyed all attacks in the range of her Clock of Doom and processed them into independent energy, it would turn into soul energy depending on the situation as per the law of danger and reward.
As such, the more attacks her Clock of Doom destroyed and processed, the more she could be efficient with her energy.
Aside from that, every attack she destroyed would increase her soul's natural recovery speed. Moreover, she had added a mechanism to the flow of energy she had created.