If you watch the Campaign run for Dark Carnival, you'd notice that the helicopter arrives much earlier than it is supposed to, even the runner had no idea what was going on apparently, it'd be really nice if we could figure out how it actually works, since it would shave off a significant amount of time. In one of my runs, I noticed that it came before I fought the second tank, not as quickly, but still before it is supposed to. If anyone has ideas, that'd be neato.

I looked into this, apparently it's something that only happens on pinion servers (pinion runs most of the official dedicated L4D2 servers). When cold stream was released this bug was apparently incredibly common, but it is less common now. It doesn't seem to be consistent, I've had it happen in a random game once but have not been able to get it again since. It can happen on every finale, including scavenge finales, making them unbeatable.

Detailed topics on the bug: http://forums.steampowered.com/forums/showthread.php?t=3052954 http://forums.steampowered.com/forums/showthread.php?t=3096241 Someone's post explaining a consistent way to test for it (haven't tried it myself but I guess it's worth testing):