You don't even need to do that, you can run Lua in a multithreaded program, as long as no lua_State is accessed from multiple threads. You can spawn independent interpreter states, have them do their job and terminate. The whole Lua codebase as such is completely stateless (apart from the state that you keep for your code). The shorter the scripts actually run, the smaller overhead you get by this.

That isn't what I asked about and isn't really helpful

Don't read it, I guess? I don't know any other way to do it, unfortunately. I'm sorry I wasted your time.