I think what we are seeing in her is the desperation of anyone who suddenly finds themself knowing something about the Clintons or possibly Obama. She knows now that Biden was never more than a puppet for the Swamp and now she is being groomed by them daily to take up the onerous and hideous job of being their puppet too. I think she has woken up to the fact that she has been handed an offer she can't refuse.
Now she like the Great Lorenzo must be force fed the missing essential ingredients of the better sort of politician/statesman. Since she is totally ignorant of history, diplomacy, economics, politics, horses and war she is in so far over her pointy head that she knows it's hopeless to continue the charade once people finally cotton on to the fact that slow Joe is in fact senile Joe and needs to be replaced by another bottom feeding democratic sort of worm that can be dangled on a string in front of the mob to fool them into thinking they are seeing the masterbaiter when in fact what they're really getting is the dummy who is at the mercy of the truly dangerous creatures that dwell in the DC swamp.
She knows she can't pull it off but she knows what happens to her if she suddenly feigns a mental breakdown in order to either avoid the string dangling bit or gets shoved into an oubliette where someday forensic scientists will exclaim, "this nasty smelling goo is the late great Vice President Harris!" Either way she knows she's dead.
Some of you might enjoy reading, Double Star by Heinlein.