I thought I'd share this so you all would be aware about this. Last week, I was playing the Dead Air campaign with 3 random players. Two of them were decent, while one of them was constantly whining and telling the team to "Hurry the hell up". That guy did not bother looking for supplies and just ran off by himself while the three of us were searching for items. When one of us told him to "Stop running off ahead", he replied with an invalid excuse which says "I don't want to sit at one place getting killed by the zombies". He didn't know that we already cleared the area before looking for items, and we were not standing at one place for very long. When we reached the metal detector, he started the gauntlet when the team was not ready yet, and then all of us got killed within 1 minute. He shot everyone after that, until we finally votekicked him.
You need patience to survive a campaign but not too much. If you are standing at one place for too long, the AI director will spawn a horde to keep you busy. Just take some time searching the rooms or the area for items and once done, you can continue (don't do this in gauntlet crescendo events)