Crescendo Event! Prepare to fight! (3)

Head up the escalators to the third floor. A Pipe Bomb or a Bile Bomb can buy the Survivors (you and your teammates) some time against the horde. Melee weapons are effective at carving through hordes of Zombies like these.

Quickly head into the security room on the third floor and shut off the alarm to stop the waves. There's an abundance of supplies here too, if anyone needs them.

Head down the stairwell and then turn right. Be prepared for a Charger (a Special Infected that charges at you) to be waiting in the narrow corridor.

The corridor leads to a room with boxes and hopefully some supplies. The exit is hard to miss.

Move up the escalator and then head towards the Safe Room (it's at the far end of this floor). Run inside! Try not to get lost by going DOWN the other escalator!