Having another person in a 360 live shoot house is a dangerous thing. I know another case where the SO, referee trailed behind the shooter. They got separated and the SO was shot. That installation moved to just the shooter with TV monitoring.
When targets come at you from all directions, you don't pause that much. Yes, you should and no shoots got shot but you don't REAL no-shoots.
I've seen referees shot with sims and paint balls. Some were scary. One referee, even with safety equipment had a shot uncomfortably close to damaging an eye. Another, a referee, started the scenario and then for some reason stuck his leg into an open corridor - got a painful inner thigh for that. He was wearing an orange vest but out came his leg. BTW, in the training, you were to shoot any available opponent target - you didn't have to wait for a COM shot. The SO were supposed to stay out of the way. He didn't.