Rescue Closets

Unlike in many games, when Survivors' health in Left 4 Dead drops to zero, they are incapacitated. If they aren't rescued, they bleed out. Survivors may also be thrown from high places (generally by something like a Tank). Regardless of the method, it all leads to the same thing: death. If the person that died was a human player, they enter spectator mode, which allows them to watch their teammates actions (except in Single Player). This was implemented into the game so that the people who died would be able to watch how their living teammates survived and learn how to react next time. Yet, in the event of a Survivor dying, there's still a chance. Once the others have traveled a certain distance from their body, the Survivor will respawn in a room (this does not happen in Versus or Realism mode), usually a closet or other small room.

However, the Survivor can't get out on his or her own, wherever they spawn. They must be found and rescued by another person. The Survivor will be outlined in an orange aura, and they will yell for help. When the door has been opened, they will rejoin the team with a Tier 1 weapon, a Pistol, and 50% health. The weapon they spawn with depends on what weapon they had when they died. If the player had a Submachine Gun or Assault Rifle, they will spawn with a Submachine Gun and Pistol. If the player had a Pump Shotgun or Auto Shotgun, they will spawn with a Pump Shotgun and Pistol. If the player dies with a Hunting Rifle, there is a 40% chance of spawning with a Pump Shotgun, and a 60% chance for a Submachine Gun.

When a player rescues a Survivor from a closet for the first time in Left 4 Dead, they get the achievement Hero Closet.

If all the Human Players in a game die, the Mission will end and restart at the Safe Room at the start of that Chapter (Or if on the First Level, the Safe Area). This is because Bots cannot navigate the level by their own (unless "sb_all_bot_team", a sv_cheat is set to "1") and rely on Human Players to help them reach the end.

Tips

 * If you are the last Survivor, move to a safe location and attempt to wait things out. Once you see the orange outline and hear the respawned Survivors shouting, run to the closet they're in (all Survivors will respawn in the same closet) and rescue them. However, if you're closer to a safe house, go there and close the door behind you. When the next chapter starts, everybody will be back.
 * If the last Survivor dies, everybody will restart at the chapter's starting safe room.
 * If you die in Single Player mode, you are given no chance to respawn, and the chapter is restarted from the beginning safe house. You can only respawn if there are other people playing.
 * In Left 4 Dead 2 on a campaign, if you find a defibrillator and are far away from a dead Survivor, go straight on because chances are they will respawn closer to you in a rescue closet.