A 23-year-old Starbucks employee preparing to enter the police force stopped her car near midnight on Westsyde Road to assist a hysterical young woman fighting with her boyfriend.
Defence lawyer Chris Thompson said Kristy Waters acted on "mistaken belief" - her help unwanted by a young couple caught up in little more than an episode of drunken yelling.
Isaac Parker, 20, stood trial Friday for assault with a weapon for the incident on March 17 this year. He pleaded guilty to two breaches of an undertaking and mischief from the incident where he smashed the hood of Waters' car with a broom handle.
Waters, now in training with Calgary police force, told a provincial court judge she pulled over and stopped, putting her hazard lights on when she saw a woman in distress. That woman was 18-year-old Jessica Lyn Kristjanson, Parker's girlfriend.
She did not know the couple.
After pulling over, Waters said she tried to get Kristjanson into her car and out of harm's way, including physically holding her.
Parker walked up the road briefly, she said, returning and clutching a broom handle.
She said Parker brandished the handle "like a baseball bat."
"He stopped and turned his upper body as if he'd swing at me. I stayed back and shouted 'go away from us.'"
Parker then said "how about this" and smashed her hood twice with the handle.
The couple walked away, where they were met by an RCMP squad car up the road. Waters said she met the RCMP car and reported the incident.
On the witness stand, Parker acknowledged that he picked up a broom handle from the ditch beside the road to confront the stranger.
"I thought she would harm Jessica. I didn't know who she was," calling striking the hood "a tactic."
Kristjanson also testified, saying "a lady pulled up and yelled at me 'ditch this d-----bag.'
"She pushed me and tried to get me in the car."
In cross-examination with Waters, Thompson said the couple "didn't want help.
"They wanted to be left alone and you wouldn't let her go," he said to Waters.
Under the Criminal Code, brandishing something that could be construed as a weapon may constitute assault with a weapon.
Thompson said his client acted in self-defence against the larger Waters.
"When Ms. Kristjanson was released, he stopped his actions," Thompson told Judge Roy Dickey.
"She (Waters) was acting as a Good Samaritan. But it's misplaced. It's a laudable goal when people want to help, but it wasn't wanted or needed. Mr. Parker acted in self-defence.
Crown lawyer Don Mann said Parker didn't act in self-defence, rather "in an angry state because she (Waters) was interfering.
"On the accused's version of events, one would wonder why a passerby would even notice."
Dickey will render his decision at a later date.