In the game, the number of building corridors you can clear from zombies depends on the specific game mode you are playing. Here's a breakdown by mode:

• Cleanup Game Mode: You start with three lives, and the number of zombies increases with each corridor. After using all attempts, you lose all your weapons. The number of corridors you can clear will depend on your skill and how effectively you manage your lives.

• Hospital Corridors: Similar to the cleanup mode, but the number of zombies increases by 1.5 times per corridor. Your ability to clear corridors will be challenged more aggressively as you progress.

• Rooms: You have one life per room, and health does not restore. Weapons remain after death. The number of rooms you can clear is limited to the number of lives you have, making each attempt crucial.

• Defense: The number of zombies increases, and you lose bought weapons after several deaths. You also need to repair barricades. The number of corridors you can defend depends on your survival skills and resource management.

• Street: You have one life per attempt, and weapons remain after death. The increasing number of zombies will determine how many streets you can clear.

• Rescue of People: With one life per attempt and all weapons available, the focus is on not killing living doctors while clearing zombies. The number of corridors you can clear will depend on your precision and strategy.

• Cleanup of Bridge: Zombies are divided into small groups, and you have one life per attempt. Weapons remain after death. The number of bridge sections you can clear will depend on your ability to handle multiple small groups of zombies.

• Training: All weapons are available, allowing you to practice and improve your skills without the pressure of losing lives or weapons.

Overall, the number of corridors you can clear in any mode depends heavily on your skill, strategy, and how you manage your resources and lives.