The other mystery is that there's nothing in the way of the sensor, unless you count pine needles on the ground. Which the sensor can't. So I jiggle the sensors a bit, discover that they're firmly wedged in place and hit the button again. Same response.
Now I'm running out of time and need to get going, so I figure I'll just close the door manually and muck with it later. I unlatch the door from the opener and discover something I've known for a while: there's no handle on the outside of the door. I don't have an actual key to the garage to lock up if I close it from the inside, so I figure I'll just be careful and push it down from the outside. Of course, it never occurs to me that maybe I should just open the other door and get out that way.
So I'm carefully lowering the door, using one panel as a lever until the space between it and the next gets too close together and then moving on to the next. I'm being oh-so-careful to avoid pinching my fingers until, for one second, I'm just not. And that was all it took. I pinched the hell out of the first two fingers on my right had, even breaking the skin. I bled enough that I had to go in the house to put medicine and bandages on my fingers. And now I look like some sort of idiot with matching bandaids.
And I still have to fix that door.