Just when you think you've got it...

I have read over the manuscript of my novel dozens of times, some parts a hundred times. I thought I had it as good as I could- free of grammatical and spelling errors, no issues with continuity, polished.
And then I was re-reading it yesterday and realized that I did something hugely dumb. Here's some insight into my writing process:
I had written a scene where Coy cuts his hand and has to go to the doctor to get it stitched up. I wanted some anxiety for Anna, so she went out to do laundry, and when she came back there would be no Coy, no Uncle Jack, and no van. So Coy had to get hurt, and then drive himself to the doctor. Simple, right?
I read it out loud to Ryan, and we both realized that if Coy had hurt his hand badly enough that he had to go to the doctor, he would hardly take the time to load Uncle Jack's wheelchair into the van. He would just drive off, leaving Uncle Jack there to explain things to Anna. Ryan also added that no self-respecting 21-year-old male would go to the doctor over a cut, no matter how much it was bleeding.
So I changed it up. Instead of going to the doctor, Coy and Uncle Jack would just go to the front desk of the hotel to use a first aid kit. Simple, right?
But I really wanted Anna to get worked up, and she wouldn't if she could look outside and see that the van was still in the parking lot. So I had the manager of the hotel ask Coy to move the van out of a handicapped parking spot while Anna was doing laundry. Simple, right?
Do you see the problem there? I rewrote this scene a couple months ago, and just noticed it yesterday. None of my beta readers noticed it either, so don't feel bad if you missed it. I, on the other hand, feel like an idiot (rightly so).
WHY WOULD THE MANAGER HAVE COY MOVE THE WHEELCHAIR-ACCESSIBLE VAN OUT OF THE HANDICAPPED PARKING SPOT????
So I had to rewrite it. Again. I couldn't just cut it out, because Coy's injury was actually important to Anna's growth over the road trip.
Bah. I shudder to think that there might be more of these in there.