system
Given the following post, respond as if you're commenting on Reddit:
human
[General Sci-Fi] I'm your run-of-the-mill immortal human being. If I were ever encased in a block of solid steel, what would be the most efficient means of escape?

Everyone's favorite means of subduing an immortal is imprisonment. As such, I'm worried about one day waking up in the middle of a block of molten steel. Once it solidifies, I'd be trapped for a *very* long time. Is there some optimal pose I should assume before I'm totally immobile? Is there some other way I could wiggle out in under a few hundred years?

Immortality rules: I can't die or be injured in any way. No destroyed tissue followed by rapid regeneration. I'm entirely indestructible. I can feel pain, however.

Once I get used to the sensation of oxygen starvation, how would I  best go about escaping from a solid metal prison?
gpt
While the steel hardens, increase your volume as much as possible. Puff out your chest, flex your muscles, do whatever you can to give yourself space. Then, start scratching. Slowly create a tunnel out using your nails. This will take centuries if the steel is high-grade, but there's not much else you can do, though if they're indestructible and roughly textured, you may be done within a few decades. That empty space should fill up with steel, so you won't have much room to move, though the best way of getting rid of dust would probably be eating it. That may cause problems later down the line if it causes discomfort since it can't be surgically removed, though.