Tank her near the back wall in Phase 1, and when she goes to take off shift to cat and dash after her with Berserk. That was the only time I went cat, and I managed just over 500k between rake, rip, shred and ravage!. That gives you a massive headstart for p2. The rest is just swipe/thrash/swipe/FFF standing underneath her, or even kitty swipe if there's nothing around for rage.