The extreme heat of the lava is enough to melt the inner circuits of the metaghost making it dysfunctional. It takes at least a second for the metaghosts' trandium to react and negate the effects of Zacharius' ability and that is enough time for him to immobilize those machines.
“No wonder it kinda felt hot here.” Emil clicks his tongue. “How’s Wrie, by the way?” He recalls that Wrie did not flinch a bit when he shouted his warnings.
Both Zacharius and Emil turn because both of them wants to confirm the yashou’s condition. Their eyes widen and jaws almost dropped looking at her. Wrie is standing only a step away from the same spot that she stands on when the bullets rained at them. It is not all that surprising if that is all, yet one clink after another, she starts to drop bullets from her hands. On the ground, without going over the line of where she stands are piles of bullets stranded as if those were simply laid flat there.