Modifying default shutdown command to gmail me one last time

Got TrueNAS Scale running with a connected UPS which is configured to shut the server down after 120 seconds of backup power (Assumes generator has not kicked in).

I get the alert emails to say “Running on backup power” but nothing to warn me “Server shutting down”. That would be really useful but there isn’t an alert tied into shutdown.

Is there a command I can add to the System Settings → Services → UPS (Edit) → Shutdown command that would use teh built in GMail Auth to send one last message saying “I tried” (or words to that effect)?