What does it mean to "step into the world of mortals and become a rock" in Lu You's "Partridge Sky"?

Being in the world of mortals is already close to madness, but (I) still want to make a career in it. I recently made an end to my previous life and found out that it doesn’t cost money to hide in the smoke. I drank wine and picked water chestnuts every day. When I was drunk, I would sleep in my coir raincoat while listening to the sound of wind and rain. I think Sanshan Zhengshen and Laozi would laugh at me when they saw it. They realized the matter forty years too late.

This poem was written by Lu You when he was in extreme decadence. The whole poem is self-deprecating that he only wanted to save the country, but he did not see that the country could no longer be saved.