It sounds like you had a 'triangle of death' event. This was what was occuring on the Prius that had a software adjustment last year. I had one on my own Prius, which I sold to myself , during the 3rd week of driving.

Why?

I was close to out of gas. As I understand it the computer shuts down the ICE if it senses that the hybrid system, specifically the traction battery, is at risk. This is so that one doesn't drive on the battery alone and damage it beyond repair. I filled up at the closest station and everything was normal. 20,000 miles later nothing abnormal.

Keep us informed please.