Sudden Death is an gameplay element in Team Fortress 2
Sudden Death is triggered when the timer ends on 2Fort, Well, Hydro and Granary. When Sudden Death is triggered, everybody instantly respawns and any Engineer Buildings are destroyed. During Sudden Death, you can not respawn when you are killed(this also means you can't change classes when you have gone out of the respawn room). You can still complete the maps objectives. When neither team wins during Sudden Death, the game ends in a Stalemate.