I'm making a computer like an arcade machine with an academic game. I'm using Xsession to replace the desktop by an application. It's working fine. But when I go out from the game it returns to the LightDM - login screen. But I desire to shuts down instead back to LightDM. It's possible to do this?

Custom User Defined Session:

[Desktop Entry]

Encoding=UTF-8

Name=RacingGameX

Comment=Just the game!

Exec=/usr/share/xsessions/gameBash.sh

Type=Application

Bash Script:

xscreensaver -nosplash &

xrandr -r 60

exec /usr/bin/RacingGameX/RacingGameXExecutable

xrandr -r 75

sleep 5

sudo shutdown now # <- that's not working

Thanks for the help!