Parliamentary video showed that after Mr. Brown made no effort to take his seat, a visibly angry Mr. Trudeau strode over and forced his way into the group. While taking Mr. Brown’s arm, in an attempt to usher him to his place, Mr. Trudeau bumped into Ruth Ellen Brosseau, one of the New Democrats also on the floor. She immediately raised her arms to her chest in apparent pain.

The situation soon became more heated. Mr. Trudeau and Tom Mulcair, the leader of the New Democrats, had an angry exchange.

“What kind of man elbows a woman?” Mr. Mulcair shouted. “It’s pathetic! You’re pathetic!”

Watching from her nearby seat was Elizabeth May, the leader of the Green Party of Canada.

She told the House of Commons that while Mr. Trudeau’s decision to physically move Mr. Brown was “most unwise,” she said that from her vantage point the elbowing of Ms. Brosseau, who left the chamber, was “unintentional.”

The Conservatives and New Democrats were less forgiving.

“I am ashamed to be a witness to the person who holds the highest position in our country do such an act,” said Nikki Ashton, a New Democrat. “This was deeply traumatic, what I will say, if we apply a gendered lens, it is very important that young women in this space feel safe to come here and work here.”