Very well. Whenever you load a new chapter of a Campaign, you might see 1 or 2 players having the names of bots. That does not mean that they are Bots. If you look closely above the characters' heads, you will see IDLE: Coach (for example). That does not mean that they are AFK. That means the player is still loading. Once the player's name appears above the character's head, that player has finished loading the next chapter. I highly recommend that you get one of these mods:
1) Rayman1103's Team Health Counter
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=121088866&searchtext=team+health+counter
2) Lemmers' Improved Stock HUD
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=121700575&searchtext=stock+hud
These add-ons will clearly display whether a player is IDLE, and your teammates' health in numbers.

There are a number of reasons to do so. I will not explain them in this section, so every reason will be in their own respective sections. Now, players will normally take 20 - 30 seconds to load. Some players will take 40 - 60 seconds (I am one of those players). Some players can take up to 5 minutes to load. Anyway, let's jump to why must you wait for other players to load the next chapter.

This is a team-based game, which means you have to work as a team. When you load first, you have the chance to heal, decide which weapons to use, and refill ammo. But what about the slow loaders? If you leave the saferoom when others are still loading, you are giving yourself an unfair advantage. This means that you are not giving your teammates the opportunity to get ready, which is extremely unfair! You are eliminating the purpose of a cooperative game! You can't just leave those poor players hanging like that! Be fair and considerate!

Each time you leave the saferoom, the player who is still loading will have the Bot taking control of their character. This is a problem for:

• Players who want to conserve their First Aid Kits
  The Bots will always heal themselves when they have less than 75 HP (50 HP on Expert) whenever a new chapter starts. If that player (Bot) has 74 HP, the bot will just use the First Aid Kit, which is a waste.
  
• Players who want to keep a specific weapon
  Every survivor bot has their weapon preferences. They will always take pistols and will not use the Grenade Launcher and/or the M60. They will always take a Tier 2 weapon if discovered. For example, if the player (bot) has a machete, the bot will immediately switch to the pistols. If a player (bot) has a Sub-machinegun, the bot will always switch to an available Tier 2 weapon (Assault Rifles, Semi-automatic shotguns, and/or Sniper Rifles).

See the importance? If you take 1 step outside the saferoom, the players who are still loading will become bots. We all know how flawed the bots are. If you know that is going to happen, DON'T leave the saferoom.

We all know the AI Director, right? If you don't, I'll tell you a bit about 'him'. The AI Director is the computer system which spawns the Infected as you progress through Campaigns. Those Infected that you see are all spawned by the AI Director. Items seen in campaigns are also spawned by the AI Director. However, that Director can get really nasty most of the time. Don't you all hate it when the AI Director does these things?
- Spawns a Tank+Horde
- Spawns Infected inside the Saferoom

Anyway, back to the topic. You already know that once a player leaves the saferoom, the Bot will take over the player who is still loading. The AI Director can spawn a Tank very early in the chapter. Bots are terrible Tank fighters. For example, in one of the Campaign games I played, I finished the previous chapter with 76 HP. When I loaded the next chapter, I ended up with 8 HP with a dead Tank beside me. What the heck!? My team just decides to leave me hanging like that and fight the Tank, letting him beat up my bot. Luckily it was only on Normal difficulty.

This is very dangerous on Advanced, Expert, and Realism difficulties. If a player finishes loading in the middle of a Tank fight, it is very likely that your team will be screwed. Furthermore, on Expert difficulty, the Common Infected are big threats. A horde can easily incapacitate you if you are not aware of them. If a player loads while fighting the horde on Expert, down they go! This is why it is very important to WAIT for the other players to load.

However, there is an exception, where a player still has not loaded after 5 minutes. This means that player's game may have crashed. Therefore, you can go ahead and leave the saferoom first. When that player loads, wait for them when the next chapter starts. If that player's "IDLE" status disappears, then that player's game must have crashed.

If you really cannot wait, I'll make another exception. You may go ahead and exit, but don't go too far. I suggest that you don't go more that 20 meters from the saferoom. That way, if the player loads, they are able to go back and retrieve what the bots drop (M60 for example). Be careful though, because once you exit, the AI director will start spawning Special Infected. It is your choice.

If you get bored waiting for others, here are some things you can do to entertain yourselves:

• Spam the vocalizer (do it at your own risk, might get you kicked)
  
• Run and jump around the safehouse
  
• Shove and push the loading player around (like pushing a bot)
  
• Shoot the walls to make a wall text or something
  
• If you have a bullseye spray logo, spray it to do some target practice

I have explained the importance of not leaving the saferoom straight away when a new chapter of a campaign starts. Other players might still be on the loading screen. This applies to Campaign, Realism, and Versus (I don't know about Versus, but I think you should do it too). I think that there should be a game feature where the saferoom door cannot be opened until all players finished loading. Hopefully, if there is going to be a 3rd Left 4 Dead game, this feature will be implemented into the game. If you have anything to add, let me know by putting them in the comments section. Have fun playing!

If you're interested, feel free to view this article I wrote:
http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=225524418

"And THAT is how you do it!"
-Nick

"I think it's time for Jack...to LET 'ER RIP!"
-Raiden "Jack the Ripper", Metal Gear Rising:Revengeance