If someone is making the room unsafe, open the ⋯ menu on their tile. You can mute their mic, turn off their camera, or remove them from the session. Removing someone stops them rejoining and quietly sends us a report so we can follow up.
Use these only when the room's safety needs it, never to shut down a disagreement. For anything serious, remove the person - removal sends us a report automatically, and urgent reports are reviewed within 24 hours. You can add detail via the "Something urgent" tab in Settings → Safety tools.