Crashes, as in actually exits without you triggering it? That's definitely very unusual; most lisp shouldn't be able to do that. Is there anything particularly unusual about your config? Are you maybe using a loadable module? If you do investigate it, you might find a reportable bug.
Yeah, I do 2 from time to time, because I use emacs as my long-running editor but also jmacs as a quick-one-off emacs-keybindings terminal editor, and so I tend to autotype C-x C-s C-x C-c for save-and-exit. My fix was to add this to my .emacs:
(put 'save-buffers-kill-emacs 'disabled "You probably didn't want to do that...\n")
which makes emacs prompt you for whether you really meant to ask it to exit. (I'm sure there are a ton of other ways to do this; this is just the first one I hit on a decade or more ago :-))
