The Fed made a fatal mistake in first promoting "fiscal" actions (during the 08 crash) and then continuing to support them well after the bottom in 2009.  This allowed Barack Obama to run trillion dollar deficits for years and, once he did so to push policies that were economically bankrupt (e.g. the ACA) and got them embedded it was faced with the reality of the creature of its own design.

It appears that Yellen thought she could leave her office with a belated "goodbye" of "normalization", after having been complict herself, and evade the impending blow up -- at least until after her chair had cooled off from her ugly ass sitting on same.