@nor5501 Do you also have neuropathy in your feet or any other symptom? This may not be related to your PMR/GCA at all. Normally problems like this are due to nerve problems and/or muscle problems. What does your PCP say about this symptom?
I have PMR and Large Vessel Vasculitis plus neuropathy in both feet. Yes, my neuropathy is assumed to be caused by the PMR/vasculitis since it is bilateral and came on suddenly. So far I have not had Foot Drop. It is possible that the foot drop is not related to the PMR issues at all. I go to PT for balance training about 6-8 times each year and this helps keep me safe, possibly you can do this once they understand what is causing your problem.
Are you using a mobility assistance device like a walker or a cane? Possibly you should do this until then find and "fix" your foot drop. Falling is a big risk not worth taking as far as I am concerned. Personally, I use a cane.