The San Francisco of the 1880s was still the Wild West and both men and women often went armed, even into Court.
Mrs. Mary Shawhan was summoned to testify about her relationship with Sarah Althea Hill. She was described as a “well-preserved, pleasant-faced, pleasant-voiced matron of about 45 years of age”, with a wealth of blonde hair, and inclined to “embonpoint,” (in other words, she had an ample bosom.)
Mrs. Shawhan knew Allie as “Miss Hill”, not “Mrs. Sharon.” She related conversations in which Miss Hill spoke of being engaged to the senator, and said that Allie wanted to sue the senator for breach of promise (not divorce).. This exchange went along in a friendly enough manner, until Mr. Tyler, the lead attorney for Allie, began asking questions of Mrs. Shawhan that implied she was less than respectable.

Daily Alta California, 10 April 1884
Mrs. Shawhan began fingering a pistol in her pocket. Her son, a young man named McCune (“Mac”) Shawhan, moved from his seat at the back of the court with his hand in his pocket. Attorney Tyler thrust his hand in his own pocket, announcing he could take care of himself.

Daily Alta California, 10 April 1884
By this time the court was in an uproar, with at least four pistols either being waved about or grasped in readiness. Tyler’s son, also an attorney on Allie’s team, drew his pistol and rose to defend his father.

Daily Alta California, 10 April 1884
The morning session ended with the lawyers from the opposing sides trading boasts and insults. After consultation with his fellow judges, Judge Sullivan came back in the afternoon with the order that no one with arms upon their person would be admitted to the courtroom during this trial.
Young “Mac” Shawhan, “small and slightly built” sounds like he should be played by Elisha Cook, Jr., the young “gunsel” in The Maltese Falcon.