Which is why I'd never have a public range. It's either individual RSO, or deal with the constant muzzle sweeping that just invites a mistake.
If you're going to run an indoor range, I think it makes more senses for it to be separate as its own business and run as a private club. You can have screening methods and do a two session one on one orientation or something.
There's not much you can do to stop a person hell bent on committing suicide, but you can certainly limit the opportunity by not handing over firearms to unknown people without at least introductory supervision. It's a deterrent, not a solution.
If it was me at this point I would consider going private membership.
It's still no guarantee it couldn't happen again , but I don't know how much more it's going to take before they end up shut down.