If you are fired for cause, specifically carrying a firearm at work, the next person to hire you is going to be told exactly why you were fired.
Dunno about that. It is a point worth considering. I'm not a labor law attorney, but I believe that only general information can be sought from the hiring company and provided by the former company, but that general information may be specific enough to cook your goose. It would likely come up that the person were fired for breaking workplace policy, and one can assume that the policy of prohibiting weapons in the workplace will be referenced, "He brought a gun to work."
If you believe that is the case, you might mitigate that damage in your new employment interviews, and address it. "We had a threat at work, and I was worried so I am a lawful carry permit holder and brought my gun to work, unloaded, for safety of myself and my co-workers."
Self defense does indeed encompass the entire threat horizon, including economics. Defending yourself from an unlikely workplace shooting isn't much good when you are homeless, penniless, living on the streets, and had to sell your guns for lunch money.
If this were me, and I was under this situation and decided to carry, I would first ensure that I wasn't breaking the rules. I would try to work for gun friendly companies. I might even ask for an exception to policy in writing, promising I would keep the gun and ammo separate an on my person concealed at all times.
Alternately, IF I decided to surreptitiously carry I would keep the chamber empty to avoid any possibility of an ND, and would carry in the absolute most discretion as possible. You'll also have to weigh the likelihood of discovery in your career, and if discovered by a co-worker the likelihood of you being ratted out.
I'm not encouraging breaking the rules, to be clear.
Personal story. I worked for a company with an ambiguous policy, or I don't recall what it was. I didn't inquire, just carried. About a year into the job, I was bending down to fill the copy machine and my shirt revealed my pistol on my hip and a co-worker was standing behind me. I didn't realize he was standing there. I immediately knew he saw it. We exchanged pleasantries but from his comments I was certain 100% that he saw it. I'll skip over the dialogue. He never reported it. I worked there for several more months (not carrying), and later resigned on my own terms and was actually asked to reconsider resigning. The topic was never brought up by him or anyone.
So, IF you carry, do so with a lot of discretion about how your movements at work (bending, kneeling, climbing, crawling around in small places, driving, etc.) may complicate your mode of carry. In other words, we take precautions in public, so double down on those precautions at work.
And, IF you break the rules, be prepared to live with the consequences as embarrassing and bad as they may be. It might include having a police arrest and escort from your workplace and maybe even being on the news, in a worst case scenario.