How could a prince Rupert’s drop-esque creature form?

I’m working on making a speculative evolution project, and one idea I had was to have a planet inhabited by silicon based life forms. One idea for a phyla was a mobile prince ruperts drop, with glass-like musculature for it to move. Any cavities within would destabilize the drop, so it would have to digest food exteriorly, limiting them to small sizes.

My question is, how would this creature be able to form? The process requires extreme pressures which is primarily made by rapidly cooling liquid glass, but I doubt any living creature (even silicon based life, which is very heat tolerant) could survive the heat. Are there alternative ways of producing prince ruperts drops that could allow for something to be placed inside without it burning?