re: Showtime dictated what Dexter's fate would be in finale? (Spoilers)

I'm not familiar with how the chain of command works, but what would happen if the writers were like "uhhh, noo...we already have an end in mind and he dies" and shotime said "no, we'll say again, he will live".

What could happen? If the writers said "frick yall, we're the writers" there's no way shotime would have the audacity to just not air a finale right? Would they fire them immediately and bring in some ragtag group of writers to make an ending to their satisfaction?