Cameron felt otherwise. In Miller���s words, Cameron argued that “Carl would keep that secret to protect his family.”
Miller also reveals that while Dark Fate’s story and script are credited to six different writers, James Cameron himself was primarily responsible for writing its best sequence, the introduction of Arnold Schwarzenegger’s newer, older Terminator.
Miller wanted Alicia and Mateo to know Carl was a Terminator, while Cameron felt they should not.
Schwarzenegger’s “Carl” doesn’t show up until Dark Fate’s midway point, when Hamilton’s Sarah Connor and her young allies track down the source of encrypted messages that Sarah’s been receiving.