Get an annoyatron and put it in the ceiling above their desk.
What is an annoyatron, you may ask? It’s a tiny little device that beeps or chirps. That’s it. But it beeps at random several minute intervals like a dying smoke detector over it’s battery’s lifetime. Which can last over 3 years…
Another problem with some teslas (and other vehicles) is that there are switching to laminate for the side window glass for strength purposes. These devices wont work in a survival situation if your car has laminated windows. LINK
I have heard it’s easy to kick out the windshield, but I’ve never had to test that theory.