The Hospital

The Hospital is the fourth chapter of the first campaign, No Mercy. It takes place in the city of Fairfield, inside of the overwhelmed Mercy Hospital. The goal of the Survivors here is to get to the roof, where they will be able to make contact with the helicopter which has been flying around the city, while fighting hordes of Infected doctors, patients, and other people.

Campaign
In this level, the Survivors discover that the hospital is overrun and the patients and staff are now infected. The Survivors leave the safe room with Tier 2 weapons. Exit the safe room and travel down the hallway. Then travel up the first flight of stairs, and you'll come to a big open room. Then go up the stairs on the far right of the room, and make your way to the second flight on stairs. Next go through medical offices, and past the emergency rooms while fighting off the hordes of Infected.

The Survivors soon find an elevator, which is the only way up to the roof where the helicopter pilot will come to rescue them. Calling the elevator will start a Crescendo Event, signaling a Horde, which the Survivors must hold off as they wait for the elevator to arrive.The elevator takes 55 seconds from being called to make it to the fourth floor and open its doors. When staring down the hallway, the walls to the left and right and the vent above will be torn down by the Infected leaving the Survivors vulnerable on three out of four sides. A good way to get past this with ease is crouch behind the gurney with ammo on it.

There is a brief time at which the Survivors may rest in the elevator before they exit onto a windy construction area of the hospital. Carefully navigating the treacherous area, the Survivors finally make it to the safe house and take one step closer to salvation.

This level is considered the most played/favorite.

Bugs
All of these bugs have been fixed on both the PC and XBox 360 version.
 * After the battle with the horde at the elevator, if a Survivor managed to become incapacitated inside the elevator for any reason and was revived once the elevator had been activated, they were left behind - the elevator rose but they did not. They would also have been unable to leave the elevator shaft, and have been easy prey to any other Infected.
 * Throwing a propane tank or oxygen tank at a Survivor in the lift would incapacitate them and cause them to fall through the floor of the lift leaving them at the bottom of the lift shaft.
 * As a Smoker, it was possible to pull a Survivor out of the elevator just as the doors were closing.
 * In Versus mode, any of the Special Infected except the Tank were able to run ahead in the level to the top of the elevator shaft and repeatedly melee the trailer in front of the elevator, eventually pushing it in front of the doors and trapping the Survivors when they reach the top. The Tank can still hit the trailer and move it in front of the elevator, but objects hit by the Tank eventually disappear making this a temporary obstruction.

Easter Eggs

 * In several of the Examining rooms there is an x-ray of a hand with four fingers, which is a reference to the cover of the game.
 * In the chapter's starting safe room, there is some Graffiti on the wall, one area of which will say that "I killed..." some number of zombies, the last number of which 53,595. This is a reference to the Zombie Genocide achievement from the popular zombie hack and slash video game Dead Rising, and that game's setting of the town of Willamette, Colorado, where the population is 53,594.
 * As you start the game, run up the stairs and into the large main room on that floor, to the right of the large door you most likely entered by, there is a door handle on the wall (a mistake more than an easter egg).