Yeah, you're definitely giving Dan too much credit. It's a good move for Memphis to get rid of Keesha, as he's guaranteed Final 2. It's only a good move for Dan because he's going to get votes because of it.
Other than that there was no clear beneficiary for Dan to get rid of Keesha. Memphis introduced the idea to Dan and Dan wanted to weigh the cons of getting rid of her and gave subtle hints to keep her, but Memphis was persistent.