Han Sen memorized the Crystal Furnace skill, then he broke the crystal wall back down and tossed the remains into the burning sea.
Although the Crocodile God hadn't clamped down on his freedom to explore, Han Sen knew that a being of such power would be to control the whole fortress. If Han Sen did something bad, like opening his core area hall, he would be immediately stopped. So, Han Sen didn't make any reckless escape attempts. Instead, he did legitimate work, shoveling and cleaning things up properly. He cleaned like a man who had come from a long line of noble janitors.
The crystallizers were a race that focused on technology. Unfortunately, it meant there were few leads for Han Sen to follow up on. There were many tools available, but Han Sen didn't know how to make use of any of them. Most of the machines were probably too broken to be repaired, anyway.