If I plead the 5th, it means that I believe answering a question or line of questions will cause me to incriminate myself in some wrongdoing. It isn't an admission of guilt to any particular wrongdoing but rather a blanket statement that I did do something I could be prosecuted for. It could in fact be completely unrelated to the proceedings under which I am being asked to answer questions about. Presumably she pleaded the 5th on advice from council because it is not straightforward or all encompassing.
I found an old article which in MHO seems to still be relevant and here is a quote from it:
Civil cases are different. In civil actions, however, there is no prosecutor on hand. The issue then shifts to whether "the claimant is confronted by
substantial and ‘real,’ and not merely trifling or imaginary, hazards of incrimination." Marchetti v. United States , 390 U.S. 39, 453, 88 S. Ct.. 697, 705, 19 L. Ed. 2d 889 (1968). Because the privilege against self-incrimination
applies only in "instances where the witness
has reasonable cause to apprehend danger" of criminal liability, the deposing lawyer should assess in advance, in light of what counsel knows about the case, whether the witness has a realistic basis for such a fear. Hoffman v. United States, 341 U.S. 479, 486, (1951), quoted in U.S. v. Argomaniz, 925 F. 2d 1349 (11th Cir. 1991).
The article is a bit long but you can find it on the American Bar Association website:
Business Law Today: Taking the 5th: How to pierce the testamonial shield
So, I am putting forth that pleading the 5th is an admission to guilt. It's just that when someone pleads the 5th you don't have any idea of what that guilt pertains to.