Aside from trying to get out of dodge, what does his leaving do to the situation?
Gonna be tough to find a willing Republican replacement. With the eyes of the world looking ever closer at the inherent corruption going on from the GOP and Trump(even beyond Russia), who would really want the oversight job in this climate? It's practically a trap role where you either become a traitor to the party by doing the job properly, or a fall guy that destroys your reputation and credibility for obstructing obvious illicit shit.