Half-Life 2: Zombie Master Office Map

Don\'t think It\'ll be easy to hide behind the desks, as the Zombie Master can see everything. [*] Survivor Objectives 1), Take the roof access elevator down into the basement. 2), Force your way to the offices. 3), Find the Boss\' Room Key by walking over the corpses in the offices. 4), Use the boss\' phone to call for help. 5), Go back to the roof and be saved.
You and your co-workers have made it to the roof to be rescued by a helicopter, but it simply dropped ammo crates and flew off. Now you have to go back into that nightmare, and call a new helicopter.