When “everyone laughed” at a mean joke, a few were laughing only because they were scared not to.

A laugh in a group is not always agreement. Some of it is fear: the quick calculation that not laughing marks you out as the next target, made in half a second by people who feel sick about it afterwards. Which means the wall of sound you heard was thinner than it felt, and at least two people inside it were on your side and silent.

If you were one of the ones laughing, you can say something afterwards to the person it landed on. One sentence, privately, is enough. If you were the one it landed on, know the room was less unanimous than it sounded.