Carrying in a workplace that doesn't allow carry is a serious issue and requires a lot of serious thought, thought beyond one-liners about being judged by twelve, carried by six, is your job worth your life, etc. While these are all 'true' statements, getting fired for carrying in the workplace is not all that is going to happen to you, should you be so fired. You will also not be hired on anywhere else, in a reasonable time frame, and will probably be at the lower end of salary offers. It's the height of stupidity to believe that 'I'll just go on down the road and get a job somewhere else."
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. No weasel words like 'he just didn't fit in our new team' or some such, it's going to be 'he was let go for carrying a concealed weapon at work in violation of our policies'. No employer is going to accept the liability, real or perceived, of not informing the next employer of exactly why you were let go.
So, if you ask me, forget the idea of tucking your pistol under your shirt, in the briefcase, or anywhere it can either fall out from or be felt or seen. You need deep concealment and placement where it not need to be handled during the day, such as in the restroom or when the team needs to take off the jackets and do some work.
If you're working in a high-crime area and need instant access to a piece, that's another issue to resolve. Finding other employment is probably the best solution. The odds are you're going to be hurt, anyway, whether you carry or not, so why stay there?