Raid mode pauses new invites and, if you want, direct messages between members, raises the verification level and can start a lockdown. One live card shows the join rate, the accounts of the wave and what Defendr changed, and gives you the buttons to ban the wave, extend it or end it. Everything Defendr changed is set back when raid mode ends, unless someone changed it in the meantime.
Example
Raid mode runs for 60 minutes and ends by itself once the joins stop.