Hahahaha another problem in very cold condition is frozen stiff film putting undue stress on the advancing mechanisms n frozem weak batteries may not transport at all... Your motor drve may seize since it is lubed with oil.
I had a problem with my RB once when camping in minus 10°f, left the camera in my backpack overnight. I tried to advance my film... A mistaske i realized as soon as i tried. No shooting that day.. Besides it would have taken us hours to warm it to the point of no condensation.
Btw a well cared for shutter won't fail because of cold unless it was lubed wrong. Most leaf shutters run dry, so nothing to slow it down.
I can appreciate mechanical over electronic as far as repairs (in my shop) go.. But not as someone might have misconstrued as field service.... Yes your batteries would be dead as your fingers fall off.