I don’t work in tv production, but my assumption is that the entire negan kill scene, including the post-cliffhanger part, has already been filmed. They’re not going to bring the cast back six months later, set up the scene/makeup/wardrobe/props exactly as it was, then finish filming that scene. The cast/crew knows…

If you’re Dwight, don’t you put a bug in Negan’s ear to kill the bro that bit your junk? Seems like an easy choice...always go for the biter.