That and some flame retardants can be simply washed away with plain water. I’d guess a limo occasionally needs to be hosed out. Do that a few times, have an ill timed Everclear spill...
Everclear is not to be trifled with, it puts Sterno to shame in the blue flame department and not nearly as subtle.
What is this other thread conclusion involving exit doors? Stretch Town Cars have the rear doors in the factory location, just ahead of the trunk, beside the original rear seat. The added “stretch” portion is in the middle of the car between the driver and the rear seat. Those closest to any fire originating in the trunk would feel or smell it first and be right beside the exit doors. If anyone was trapped it was because the driver didn’t stop so they could get out. Given the ugly choices at hand I’m surprised someone didn’t jump out of the moving vehicle. Incapacitated somehow?