A better ending would have been... (spoilers)

She manipulates Kip into leaving the apartment AND killing the boyfriend.

It is then revealed that she and the "boyfriend" were co-owners of the building, say brother and sister or husband and wife, and just 'acting' to get Kip out.
But she double-crosses both men....
She inherits entire building and has the rent control guy out too.

This would have been a much better twist.
I thought of it when she said "one of the owners".