We don't necessarily want to purposely crash our server, but it would seem this is what would work:
1. Set your config file to unload sectors after 5 seconds.
2. Set your undeathenator in a far away sector from your test sector and tag it.
3. Create an entity with a lot of Power Auxiliary blocks on it.
4. Place a warhead next to these.
5. While in astronaut mode, without godmode on, detonate the warhead and ensure you die from the subsequent explosions.
6. After respawning at your undeathenator, wait long enough for the sector with your test ship in it to unload.
7. Return to the sector using the /change_sector command.
8. Shoot at the entity with another ship's onboard weapon's systems. A class cast exception should start repeating.
9. After the class cast exception has occurred, attempt to remove the entity with the "/destroy_entity_dock" and then "/despawn_sector" commands. This should crash your server and it should crash with no error code (thus if you have scripts set to catch error codes and restart the server when it shuts down abnormally, they will not catch this).