Leave the group that laughs at whoever isn’t in the room. You’re next on the menu.

A group that entertains itself by taking apart whoever stepped out is running a rule nobody says out loud. Everyone takes a turn. Sitting there while it happens feels like safety, but it is really your turn not having come up yet, and some part of you can feel that even while you are laughing.

Start by not adding to it. No speech required, just stop supplying material and change the subject. Notice who else goes quiet in the same moment. Those are usually the people worth sitting with, and there are more of them than the noise suggests.