HotDog - wrt to people who are invalid / infirm (be that physically and / or mentally) evacuating from an aircraft in an emergency... the plain and simple answer is that they are not going to be able to evacuate, and that's a risk that they (and those travelling with them) have to take. That said, quite whether they are aware of the risk and / or likely outcome is another matter?!
Life is full of 'risk'; Nobody gets out alive!
