Assuming `M-x` still works correctly, in emacs you can explicitly run any command associated with a shortcut.
So in this case, `M-x save-buffers-kill-emacs`, or simply `M-x kill-emacs`, could have done the job.
(if this still didn't work, you could even have written "(kill-emacs)" in a buffer and ran it with `C-x C-e` :D )