High pitched whine and warning lights

My daughter, a young driver, is currently in rural Maine with her 2004 Prius--with 160K miles. It went to the shop last week, before heading out on a 1200 m trip, and was given a clean bill of health (it's had a TON of work, including new 12V and new hybrid battery already).

So she got to Maine last Thursday and the dash lights went out and the car wouldn't turn off. That smells like a combination meter--based on our experience with another Prius--so we ordered the part and scheduled service.

Two days later the dash lights came back on. Of course.

This afternoon, she turned the car on and the !! light and the ABS light came on and the car made this sound:

She said the car FELT like the brakes weren't working right.

We walked her through reading codes on the reader in the car. There were none.

She drive the car to AutoZone. They found no codes either.

Does anyone know what this likely is?

How dangerous is this car?

She is supposed to be starting a new job in upstate NY next week and she'll be in VERY remote locations most of the summer.

Thanks,
Biz