You will become incapacitated if your avatar's HP is reduced to zero, and are then given the choice to continue playing or not. You can also revive other fallen players at the cost of your own Combat Points.
You are able to continue playing the stage by consuming the same number of Combat Points that was required to enter it.
Tapping this option will remove the options window and your body. You will be revived if another player wishes to revive you. Tapping the cross icon on the top left of the screen will return you to the options screen.
This button acts as the same function as the Exit button. There will be no confirmation window however, so be sure that you want to quit the dungeon before exiting.
Other players that become incapacitated will show a cross icon in their character icon. Tapping it will consume your own Combat Points and revive them. The number of points consumed is the same as the number required to enter it.