Probably sharing the equipments.
Jack guy finish 1 rep and trying to add weights. See him like want to take the small weights at the side.
Maybe he thought the girl was fooling around and didn’t think that she will try to lift it.
From the direction of the seat, the guy is probably benching, if squat, it should be other direction so you can fall and to the floor instead of getting stuck at the bench.
The mother want show off to daughter maybe, and then died.