Stay Silent. If the person with the personality disorder is in therapy, then it's up to them to work through various issues with their therapist, to avoid these things popping up in the workplace.

I'd say, 'mum's the word'. Besides, why worry about something that may or may not happen. Can't predict the future. And those without PD's, may behave the same(perhaps) as people without under duress, etc. Point being, it could hinder employment, most employers are not well versed in mental illness.

And I'd be leery to consider that forewarning could be perceived as making an excuse for any future behavior? If that makes sense?