If you want to do the supported 22 mile run, I would go with the plan of running 22, take the DNF and get your SO to pick you up.

The other possibility that you did not present is throwing your plan out the window for that day. You could skip the 22 all together. I know it's hard to believe but physiologically speaking it's not going to harm you to miss one of your long runs. Mentally though you have to be able to trust that you're body can still do the marathon without that 22 miler. The psychology of that run might be important. Do you have another long run the next weekend and then a taper? Or is that your last long run?