Windows: Sorry, Dave, we can't shut your system down right now, you have 3 apps keeping it from shutting down and we have 37 updates to Edge Browser to install... Have a nice day.
EWX_FORCEIFHUNG 0x00000010
Forces processes to terminate if they do not respond to the WM_QUERYENDSESSION or WM_ENDSESSION message within the timeout interval. For more information, see the Remarks.
If the EWX_FORCEIFHUNG value is specified, the system forces hung applications to close and does not display the dialog box.
You'd have to watch out that you don't let the system store a memory dump, of course, that'd be the exact opposite of what you want.
The way we implemented the self-destruct (currently only available in Linux), it locks the screen before attempting to wipe the LUKS Header. I imagine we'll do something similar in Windows, so the worst-case would be the soft shutdown hangs but at-least the screen is locked immediately.
Hopefully we can force an immediate, uninterruptible, hard-shutdown in Windows, too.