I don't understand how that escalates to the point that he gets fired over it, though, unless there was something deeper implied by what was announced at demo day.
Edit: Theres a rumor floating around that "it" was the GPT store and revenue sharing. If that's the case, that's not even remotely a safety issue. It's just a disagreement about monetization, like how Larry and Sergey didn't want to put ads on Google.