Other suggestion of each member leaving one by one as he speaks because it would be less disruptive overall and would continually bug him to see people walking out. But because it’s not one moment, he won’t be able to stop and address it and flip the narrative while speaking.

I love the suggestion of leaving something behind on the chairs. So maybe leave behind the Ukrainian scarf on each seat.

It would be great if they all took off their suit jackets before walking out. Wear a black tshirt only, like Zelensky. Use Trumps tactics back against him.

Everyone should wear the same color, black would be fitting. Wait until Trump finished his first line, THEN everyone gets up together and walks out. Make him think he has his audience and then rip it away. Have some symbol they all wear that symbolizes standing with Ukraine, a pin or scarf