I don't think she can be charged with a misdeamenor. Congresspeople on their way to or from work cannot be detained or charged with minor offenses. Its in the constitution.
The protection doesn't apply at all to criminal cases, since it excepts "treason, felony or breach of the peace" (Williamson v. U.S., 207 U.S. 425 (1908)).
She cannot be detained on her way Congress due to minor offenses. It doesn't mean that she gets away scott-free and doesn't have to answer for the offense. The idea is to prevent police from (intenitonally) keeping Congresscritters from votes for minor offenses (real or imagined), not to exempt Congresscritters from the law.