The only reason she failed was because she didn't understand how to unlock the firing mechanism.
From an article:
Alice Boland, 28, who was charged in 2005 with threatening to assassinate President George W. Bush and members of Congress as she waited in line at U.S. Customs, is again charged with plotting a violent attack. On Monday, after pacing in front of the school gates during car pool and visibly swinging a gun, she tried to shoot two faculty members: the director of the high school, Mary Schweers, and an English teacher, Chris Hughes.
The police charged Ms. Boland with attempted murder and unlawful carrying of a firearm. The only thing that stopped her, they said, was that she did not realize the gun was locked.
“We were very fortunate she did not know how to take the lock off, or this could have been a tragedy,” said Earl Woodham, a spokesman in Charlotte for the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.
The authorities are investigating whether Ms. Boland was required to disclose her history of mental illness when she bought the gun. A small firearms store in Walterboro, 50 miles from Charleston, sold her the Taurus PT-22 pistol on Feb. 1. She filled out a federal background check form and was approved.
She appeared to have bought the gun legally, Mr. Woodham said. Gun buyers nationwide are required to disclose mental illnesses only if they have been committed to an institution or found “mentally defective” by a judge, he said.
“Unfortunately, there are a lot of people who are mentally unstable but who would not technically be declared mentally defective,” he said.
Ms. Boland’s 2005 brush with law enforcement came when she became upset with the slow process of getting through Customs in Montreal.
“I am going to kill President Bush with a gun,” she said, according to federal court papers. “Just give me a gun. I am going to come back and shoot you all.”
The federal charges were dropped after she pleaded not guilty by reason of mental incompetence. ...
Parents were grateful for the quick action by administrators, who used a well-rehearsed emergency plan to secure the campus and stalled Ms. Boland at the gate. Two weeks ago, in response to the Newtown, Conn., massacre, the police met with school officials to rehearse the protocol for a school shooting.
The mayor of Charleston, Joseph P. Riley Jr., said that the incident was a “wake-up call” and that he would encourage South Carolina legislators to tighten restrictions on background checks for mental illness.
“If you threaten to kill a president of the United States, so many alarm bells should sound when you go to buy a gun,” he said. “We could easily be talking about a homicide or multiple homicide. It’s a miracle we’re not.”