Although I don't hunt, I use a Redhead Target Premier to shoot trap. Occasionally we shoot doubles (load two shells), but usually singles (load one).
The ejectors work on both barrels simultaneously, whether there's one shell in there or two.
If you break the gun open with, how should I say, some energy, the shells will fly over your shoulder. Even in trap, that's not good, although they are much easier to find. If you ease the gun open while placing your left hand over the receiver, the shells will stay in the barrels, allowing you to remove them individually.
Hope this helps.