Something never struck me before
I rewatched this tonight. When Loomis and Nurse Chambers get to the sanitarium and Michael attacks the nurse and steals the car, Loomis is absolutely certain it was Myers. But he didn't see him, and Nurse Chambers didn't see his face or even know him. I get Loomis probably believed it was Myers, even 'knew' in his own mind, but straight away he's acting like it's a confirmed fact. They wouldn't have actually known it was Myers until the staff had done a head-count later to see who was missing.