Ms. McMillan said she had spent that St. Patrick’s Day on a pub crawl with a visiting friend. They took a cab to Zuccotti Park in the hopes of finding another friend, and a less crowded Lower Manhattan bar. The friend, Lara Wasserman, an opera singer, testified Wednesday that she and Ms. McMillan each had about seven beers in the four hours before the incident. When asked by a defense lawyer, Martin R. Stolar, if that was excessive, Ms. Wasserman said, “No, we went to school in Wisconsin.”

Closing arguments are expected to begin Friday.

Ms. McMillan, a labor organizer who faces seven years in prison if convicted, expressed remorse.

“I’m really sorry that officer got hurt,” she said. “People are doing their jobs; stuff happens.”

She added that part of what drew her to the protests at Zuccotti Park was the hope of pushing the city to negotiate better contracts for its police officers.

On cross-examination, Assistant District Attorney Erin Choi hammered on records of Ms. McMillan’s medical examinations from the days right after her arrest. None specified that her breast was groped.

“It says I was abused,” Ms. McMillan said. “But it does not say specifically my breast.”

Earlier, Officer Bovell testified that he put his hand on Ms. McMillan’s shoulder to steer her out of the park after she refused a command to leave from a second officer. He also admitted to being suspended for several days by the Police Department for fixing traffic tickets in 2010.