Deadpool volume1, #5: Deadpool's healing factor is fixed, but diminished. Wade is ready to pay back Killebrew for all the horrors committed on him in the Hospice. Siryn vows to stop Deadpool killing Doc Killebrew at all costs.
She won't leave for him to waste the Doc, so he yells "LEAVE!!"
He doesn't kill the person who totally destroyed his life...because of the woman he loves.