One day, Williams testified, a woman expelled a fetus into the toilet and she saw its arm moving. Williams said she took a pair of scissors and snipped the spine as Gosnell showed her.
"I did it once and I didn't do it again because it gave me the creeps," Williams said.
Back in the witness stand for a second day, Williams told McMahon that Gosnell reassured her that what she saw was "involuntary movement, a last breath" and that abortion drugs had already doomed the fetus.
"He told you that it was dead already," said McMahon.
"Yes," Williams said.
"So when you snipped the neck, you didn't think it was a live baby, you thought you were snipping a dead baby?"
"Yes," said Williams.
Prosecutors have argued that the babies were killed because Gosnell either did not use the drug Digoxin or did not administer it properly so that a live birth resulted and Gosnell allegedly killed them with scissors.
According to earlier trial testimony, after the U.S. Supreme Court affirmed a federal ban on the rare, so-called live-birth abortion procedure in 2007, late-term abortion providers like Gosnell switched to Digoxin, a heart drug, to kill the fetus in the womb.
Although expert witnesses testified there was no medical reason for Gosnell to cut fetal spines, Williams said Gosnell told her it was to "ensure fetal demise."
McMahon also focused on a statement Williams wrote while in prison in 2011 in which she said she administered pain medication to abortion patients "to try to make them more comfortable."
"I'm sorry but I help people, not hurt them," Williams wrote. "Yes, I wasn't licensed to give meds but I did it under the doctor's orders."
Williams worked at Gosnell's Women's Medical Society clinic in West Philadelphia from late 2008 until it closed in February 2010 after a drug raid by a state-federal task force.
Williams had been charged with first-degree murder in the case of the newborn whose spine she cut. She pleaded guilty to third-degree murder and agreed to testify for the prosecution hoping for a lighter sentence.
Williams also pleaded guilty to third-degree murder in the Nov. 19, 2009, death of abortion patient Karnamaya Mongar during an abortion.
Prosecutors alleged that Mongar, 41, of Virginia, was overdosed with Demerol. Mongar's death is also the basis of one third-degree murder charge against Gosnell.
Gosnell, 72, is also charged with seven counts of first-degree murder involving infants born alive during illegal late-term abortions and killed with scissors.
Contact Joseph A. Slobodzian at 215-854-2985, firstname.lastname@example.org.