Like you said, 40-100k PSI. That’s WAAAAAAAY beyond anything a survivor could reasonably put together without a factory of tools and a how-to manual. Then you’d have to lug it around and that… that would suck.
Laser cutters on the other hand are pretty common and smaller. Relatively easy to build and SEEM to be more accurate, based on a quick wiki check. We could fudge a recipe for it with any laser device, some assorted components, and a skitterbot.