Agree. Every field attracts certain types. Every hospital I work had has had problems with the surgeons being irritable, narcissistic, etc. (Of course this is not every surgeon. My dad is one, he's a very nice guy though he's somewhat schizoid).
No one should be excused from not being able to do their responsibilities. If you can't do them--you shouldn't be in the field. Yes, of course, if someone is disabled, the institution has a responsibility to do what it can to make accommodations. E.g. a doctor in a wheelchair needs an elevator and ramp. Borderlines, however, even in therapy under DBT guidelines, are expected to do their responsbilities and be held accountable for mistakes they make.
I mentioned in other threads years ago that there was a severe borderline in my residency program. The program should've set objective guidelines to her that she needed to follow and clear boundaries, and if she didn't meet them, they could easily argue that she should be removed.
If a resident had borderline PD or a different one hurting their responsibilities, the biggest leeway I think I'd try to provide them if I were in the position would be for them to get therapy outside the institution, or tell them to take off time and get treatment, maybe some time off to get things in order, but never ever never never excuse them for poor work.