Should I Rat Out a Toxic Co-Worker?

Dear Evil HR Lady,

I have a toxic coworker in my research lab. She is controlling, neurotic, and passive aggressive. I have to interact with her since she manages all the data for the studies I work on. My boss recognized her poor treatment of her direct reports and assigned those people to report to me instead.

In addition to her bad behavior, she also is inefficient, resistant to change, incapable of handling tasks like scheduling , and takes weeks to do what should take hours. I cannot bring concerns directly to her because she gets extremely defensive and rejects any suggestions I make in a knee-jerk fashion, which requires me to get director approval on everything in order to make any changes.

I am leaving the job to go to grad school this coming fall but am hoping to come back to the lab after I have my degree (at the suggestion of the director). Should I keep my mouth shut, leave gracefully, and hope things are better when I am looking for a job there later? Or do I say something to my director, who is always very responsive to my concerns? Honestly if she is still in the lab when I am looking to come back, it might sway me to look elsewhere, and I know the director would be upset if that were to happen since he really likes me

Go to BNET (sorry for the click through) and read what to say about a Toxic co-worker.