The monster inside the gate, be it living or dead had exploded into mana particles, but that didn't mean that the monsters that were already killed by the raiders of Crimson Lotus guild vanished without dropping the loot they were supposed to drop.
Still, it was a loss that they couldn't kill more mid-bosses and get their loot, but it was fine since it was not the biggest loss they had in this gate.
The thing that felt like a real loss to them was the fact that the hidden boss didn't drop anything. It just vanished into particles.
But they were not sad, after all, their profits were enough to outweigh the losses by a lot.
Even if the hidden boss didn't drop anything, there was still the boss there and the boss did drop some very juicy loot, but that's for later to be disclosed.