Failure to launch

Just had a terrifying experience. Sitting at a light about three cars back on a busy four lane divided highway. Light turns green, foot off brake and on accelerator; car cuts off. Thought it was the idle stop but I hate that thing and almost always cut it off after initial start. Sure I did it this time. In looking at that button, notice that the vehicle appeared to be in neutral. Hit the Park button then Start, nothing. Everything else was working fine. No codes, radio okay and windows worked. Kept pushing buttons, engine off, engine start, Park, etc. Nothing worked. Emergency flashers on and working. Got my wife and dog out of car and safely on shoulder then tried a few more times to restart, nothing. Nice fellow pulled up and offered to push me out of the road. In anticipation, I pressed Neutral button, nothing. Frustrated, pushed Park then Start and lo and behold it started Pulled off road, retrieved my wife and dog and drove home, about 10 min. This is a 2020 Elite with 20,000 mi. Scary stuff as this was a very busy road.