Ya, probably phosgine gas. Most clorinated hydrocarbons generate it.
If the fire's that bad I would advise running away. Teflon needs some 600deg to burn. Plus the entire electrical system would require a few pounds at best.
Most buildings have some level of teflon wire as it's rated for plenum grade. (usually data cables in overheads)
PVC on the other hand generates tons of smoke. (this will get you quick)
I'm sure some have seen the Ford explorers and pickup trucks on the side of the road with smoke bellowing out of the cab.
