In a video posted to the Council of Canadians' verified Facebook page Wednesday evening, a woman is shown standing in front of the stage where Trudeau is standing; she appears to unfurl a banner that references the prime minister and compensation for the "mercury crisis." She is heard saying "people in Grassy Narrows are suffering from mercury poisoning, you committed to addressing this crisis," while appearing to be removed from the room.

Trudeau, still on the stage, is heard saying, while facing the direction in which the woman was taken out of the room, "Thank you for being here, thank you very much for your donation tonight, I really appreciate it," which draws cheers and applause from the crowd.
The Grassy Narrows protest in Toronto was at the Omni King Edward Hotel, where Trudeau was scheduled to appear at a Laurier Club donor "appreciation event."

https://www.cbc.ca/news/canada/thunder-bay/grassy-narrows-mercury-centre-1.5073665