Completely new word to me.
My thought is that it is not a "Demon from hell" talking here it is a room full of writers who have built careers on the spoken word and definitely know it's power. Every word of dialogue in a popular show like this is scrutinised and has to be justified so I would like to know why they felt "every demon for themself" was not adequate and they shoehorned in this clunky, unwieldy line that seems to have no context to it.
Personally I'm offended by bad writing and of smart people trying to using language to show off how clever they are.