The Tiffin that crashed apparently went through a lot before it stopped. And, keep in mind, we are seeing the coach AFTER it was delivered to the holding yard. The structure may not have been completely separated during the crash.
Maybe the Original Poster will find out from the 'driver' and let us know the condition right after the accident. We don't know if the Zephyr was lying on it's side or not after it crashed.
rjxj, I think you have a false sense of security in your 'assembly-line' vehicle. I've seen trucks that crush up pretty bad in accidents. And, if you have a 5th wheel, it's mighty big trailer behind you that will change ALL the dynamics of everything.
Safe travels,
MM.