There was once a plan to have a secondary unwinding mode that just aborts the thread and frees it's memory without running destructors. I didn't particularly like it though. I think niko has some fanciful ideas as well.
As @matklad suggests though I think dealing with double panic, oom and other unexpected catastrophes should be done most reliably with process isolation. It would be great if there was an easy to use framework to do this. There are already some good cross platform tools available. Something built on ipc-channel and gaol would be pretty solid.