I clearly have no reason to trust in your mental health. Why should I, as your employer, want to make it easier and more convenient for you to have access to more lethal purpose-built hardware?
If you have paranoid questions about my health, isn't that just more reason to have more armed people on the premises to keep me in check? Or at least mitigate whatever damage I could do? If I do fly off the handle, and you've disarmed everyone, there isn't a lot short of me running out of ammo that is going to stop then is there? I sure as hell am not going to care about laws and posted warnings if I'm already bent on murder.
As it is, with my size and training alone I could wreak a fair amount of havok with no weapons at all. And no one here could stop me. However, an armed 8 year old, who was a decent shot, could bring me down in a heart beat.
Guns save lives. Guns in the hands of the law abiding are a deterrent to criminals and loonies alike. That you can't figure out or accept that simple fact says a lot about you.