I'm currently trying to tweak the basegame dropships so that when they lose their doors, they are forced to open the hatch and unload all cargo. I feel confident that I could actually get the hatch opening part to work, but I can't think of a way to have the dropship detect if its doors are missing.

In your Create(), do a check through all MOs, find ones that have the same PresetNames as the doors and the same RootID as the dropship. Then in your Update, constantly check if your door IDs are 255 (meaning they're destroyed) and then do your door controls if so.