Originally Posted by justD
Have to be up also because the emergency services have to be able to look inside!
The primary and only real reason is so that cabin crew can see outside the aircraft in the event of an evacuation... the ability for the emergency services to be able to see into the aircraft is an ancillary ability. If the emergency services need to be able to see inside, the chances are there is going to be gaping big holes for them to look through...