The furnace had become semi-transparent under the heat of its own flames. The coin hit the side of the furnace with so much force that it started to cave in on itself. A small hole formed in the surface, and the coin disappeared into that hole.
It felt like time was standing still. Dragon One and Dia Robber didn't see the coin come out on the other side, so they assumed that the coin was still stuck to the furnace where it had originally landed. They doubted the coin would have enough power to penetrate the furnace.
But then they froze in disbelief. The whole furnace was imploding. As if a black hole had formed at the center of the furnace, the whole thing collapsed in on itself. The huge furnace twisted into a small chunk of metal.
And this minimizing process continued without stopping. It was like a soda can being crushed under someone's foot. The power inside the furnace continued to collapse its structure.