Thanks for your advice, whirlcool, but 1) I couldn't have unplugged it without using a ladder, since the outlet is in the ceiling, not to mention being blocked by the car immediately under it; 2) unplugging it made the opener inoperative (obviously). There was/is no outside handle or any way to open it without coming inside, by way of the living room and kitchen, and using the emergency release. It was an unacceptable status quo.
Anyway, I have a new opener and my problem is solved. I'll file your advice away if the situation ever arises again.
Anyway, I have a new opener and my problem is solved. I'll file your advice away if the situation ever arises again.