After Marie kills Dinah, Ms. Mead acts quickly and attempts to gun down the witches. Cordelia uses magic to cause the robot to explode and while Michael is distracted being distraught (this is the second time he's seen his "mother" die after all) Madison swoops in to grab Mead's machine gun arm and render him temporarily out of commission. Myrtle grabs a lock of Michael's ("smooth as silk") hair and rushes off to the tub with the others to perform the time travel spell. Brock, still pissed about being left behind, stabs Mallory and gets set on fire by Myrtle for his troubles. While Cordelia and Myrtle scramble to get a dying Mallory to the tub, Madison, Marie, and Coco do their best to keep an awakened Michael out of their way. He kills them all in quick succession before confronting Cordelia.
Mallory isn't strong enough to complete the time travel spell — she doesn't have the power and she's just been killed for the second time. She could probably use a juice box and a nap right about now. Cordelia confronts Michael and lays into him; she calls him a scared, little boy who's always followed other people like Ms. Mead and his father rather than being his own person. And rather than let him have the satisfaction of killing her, Cordelia kills herself, sacrificing her life so that Mallory can gain her powers and rise as the new Supreme.