I am having the same problem, i entered the code fffreak said into a batch and it kept repeating.
Displayname i recommend creating a new shortcut on your desktop (or where ever you want), when it comes up it will ask for location, enter this into the field, shutdown -s -t 12
then call it shutdown or what ever you want, when executed this will shutdown your computer in 12 seconds just like you want, hope this helps