That might work in "no weapons" areas where you're not employed, but it's very risky at your place of business (assuming you want to keep your job). If I carry in a business that has a no weapons sign, at most I risk being asked to leave. If I carry at my job and someone sees my weapon print, I'll be looking for a new line of work. Also, an employer could ask to search my vehicle or person at any time. I'd be within my rights to refuse, but they would be within their rights to fire me if I did.
And I can just imagine the phone call that would go down when prospective employers called for references...
"Would Cue-Ball be eligible for rehire at your company"?
"Could you explain why not"?
"He carried a loaded gun into the building, against company policy".
The fact that you're acting in your own best interests (and likely, the best interests of your fellow employees) wouldn't matter. The prospective employer would likely see you as a dangerous, unstable person who is looking to cause trouble. Unless, of course, you're applying for a job at the local gun shop.