Terrible. I would not wish that even on the Iranians, potential enemies. All Lives Matter.
As you ask, was this even an accident?
I know nothing about flying, but I’m guessing that ejector seat doesn’t just spring up at the slightest turbulence.
https://www.popularmechanics.com/military/aviation/a26193/how-pilots-eject-from-fighter-jet/
In newer two-seat jets, the ejection seats are synchronized so activating one triggers the other. But in the older T-38, each person needs to take care of himself or herself. The co-pilot sitting in the rear seat needs to go first—otherwise the rockets from the pilot's seat will burn the person sitting behind. After you fly out, the seat itself falls away. The chute automatically deploys if you are at low enough altitude, and if all goes well, you should float to the ground at a speed that won't kill you.
It takes effort to eject. Older aircraft, usually had separate ejection seats, independent of each other. Newer aircraft, can eject both seats, using one ejector. Each type aircraft is probably designed differently. Obviously, something went terribly wrong. Maybe an electrical short, but I wonder if anyone considered suicide, by ejection seat? Who knows for sure?