Although Sanderson and John can easily shift the blame to Peter Randall and away from Art Lee, John has his misgivings. Why?

After John learns that Peter Randall also performs abortions, he and Sanderson realize they can shift blame away from Art Lee and now point to Peter Randall as the abortionist. However, John has misgivings. Just as he does not believe Art had performed the abortion that led to Karen's death, he seriously doubts that Peter had performed that abortion. Sanderson thinks that perhaps the fact that John likes Peter is clouding his judgment. But John does not want to free one innocent man by framing another man who may well be innocent, too.