should i dropkick my kid brother for going into the garage?

lol be thankful. timing chain skipped a couple teeth in my ramcharger and ended up getting a good deal on an 89 roller cam motor to replace the 76 hydraulic lifter engine.(84 ramcharger, original motor had bearings that were extremely loose and was replaced a year after I bought it) Anyways, I regasketed the motor and had it sitting in the garage(ran in for a bite) and I come out and my brother and his friend are grinding away at some welds on a stupid motor scooter project and where are the sparks landing? right on the passenger side head that I had left open with no valve cover. I lost it. He damn near crapped his pants the look he had on his face.