The shot to his stomach was hard, and Peter's breath rushed out of his lungs with it. He saw her eyes flash, but then turn back to black. He would have retaliated with electricity - she wouldn't have time to block, this close - but then Xander had to get involved. Noble, but idiotic. The bruising done to his ribs by it was already healing. Still, lightning would still hit Xander as well.
Fan-fucking-tastic.
Peter drew back his own arm and let it fly at Willow's face, putting as much strength and telekinetic force behind it as he could muster.
Stay back, Xander, he mentally sent to the boy. Get the damn antidote from Cordelia!
Then he lifted a hand, guiding it to wrap a similar one around the witch's heart with telekinesis, and squeezed.