This is actually a very good suggestion. As a former shop supervisor, I would always tell the guys to make sure that someone else knew if they were going to be in the shop alone. That way someone could check up on them after a while.

Some crazy things happened in the 5 years I was there, once a guy was turning a steel shaft and left too much hanging out the back unsupported, it started to wobble and then broke off and went straight up into the roof and stuck there! Had to get a roofer to fix the hole.

Another time a guy put a 2000 rpm max grinding wheel on a 10,000 rpm die grinder, again, it whizzed along for awhile, then flew off and broke the window on our vertical cnc machine.

There were no injuries I can remember in my time there, just close calls. If someone were hurt, though, I wanted someone else to be around to call an ambulance.