The man who shot Tiller is indeed a murderer, but he is no more a murderer than Tiller. What grave medical emergencies did Tiller save women from? Please name the specific medical conditions these women suffered from that required murdering the life growing inside them. There aren't any that would fund Tiller's slaughterhouse.
Women with high risk pregnancies are put on bed rest and monitored. Very, very, very rarely does any condition call for the death of the baby. If anything, the situation calls for monitoring and if necessary, delivering the baby early via c section and then the baby can be taken care of in the NICU.