He potentially could work in a casino. Not only because of the shift, but because people in casinos don’t pay much attention to workers around them, they are so glued to their slot machines. I don’t gamble - I observed what was going on on the floor, gamblers are so focused on the game, anyone could fly under any radars there. They may pay some attention to the croupiers or people greeting them or giving them out money, but not people on the floor when they are playing.
And casino life is pretty isolating, I think.
(Or a person who lost a lot could be so angry, he’d take it on two innocent people. Not very typical, but happens). MOO