You need to play
only in rescue mode. In ranked matches you need at least 4 players and in private matches you need at least 3 players.
Only the survivors can be revived. When a survivor have no more life, he fall on the ground with a gun and a teamate can revived him with the
for a limited time. A Solarii can finish a survivor on the ground but he can defend himself with the gun.
There is at least 2 rounds so we are the survivors and the Solarii at least once