AC won't start with a door open either. However, once it's going, you can open a door and it keeps going. I was working in my garage and wanted to cool it off a bit, so i started up the AC with the windows down (it will let you do that) then opened the back lift gate.
I'm sure it wasn't a great idea from an energy standpoint, but it DID cool things off in the garage and i got a bit of a chuckle out of it. One of the many unique things you can do with an EV, but would be a HORRIBLE idea with ICE.