[Evan Thomas]

Siggygirl, the first thing to do is to postpone the appointment (I'm assuming there's an appointment involved) until after the panic button is in.

That's assuming you have a really good reason for not just canceling the appointment or turning it over to someone else.

Who will the panic button summon? How long will it take them to arrive?

If it's longer than a few seconds, and you probably should assume it will be, you need some sort of backup plan/weapon in any case.

I'm not sure introducing a gun into this situation would be a good idea: first, if you're not able to carry it on your person, how secure will it be? Will it be in a desk drawer? In your handbag? Second, will you be able to reach it in time to do any good? It would be an absolute last resort in a situation like that, and if it's not on you, I'd be concerned about being able to get to it at all.

A knife or other stabbing weapon is a bad idea unless you're trained to use and retain it, I think, if you're confronting someone larger and stronger. And in any case, you have to be too close in order to use it. You don't want to be within reach.

The pepper foam is probably your best option; I say this partly because the threshold for using it (non-deadly force) is going to be a lot lower than for using deadly force... so you'll have more time to deploy it on someone who's unruly and threatening.

As another middle-aged woman, I'd want the panic button, and the pepper foam, and I'd arrange for another, non-tiny, person to be present during this meeting. Anything less isn't safe for you, and you should decline to see this individual.

I have some experience, albeit second-hand, with a situation like this: my mother worked in a large Federal bureaucracy, and was deliberately set up by her boss (who wanted her out) in the identical situation: a psychotic client who was known to be homicidal, door closed... it turned out OK, but she said afterward that she wished she had just said no to her boss...