Russert's apparent disappointments lead her to start a new life in Europe with a French diplomat, and she is gone from Baltimore at the start of Season 5. She appears during that season's finale, having returned briefly to Baltimore to help the squad investigate Felton's death.
The narrative depicts Russert's relocation to Europe as a consequence of her disappointment, which prompts her departure from Baltimore at the start of Season 5. She reappears during the season finale to assist the team with investigating Felton's death, highlighting a temporary return to Baltimore.