SAS Zombie Assault Wiki

Vaccine is the second mission in SAS: Zombie Assault 4, unlocked at level 2.


She talks about time and at the end of mission

After finding no signs of life other than zombies on Planet Thera, the compete destruction of the infested planet by a Jolt ship is verified in defense of the future to mankind.

However, a zombie outbreak has occurred on planet Aartis, where the remaining members of the human race resides. At the same time, a vaccine has been found in a laboratory on planet Thera by Combot, vital to the survival of humans.

The destruction of Thera cannot be delayed or stopped as the attack is already in launch. Thus, SAS soldiers are deployed to the surface of Thera, where they must take a subway to the lab, get the vaccine, and escape to a dropship in less than fifteen minutes before "Operation Disinfect" commences. If they do not return to their drop ship in time they will be obliterated with the planet, destroying the vaccine and the soldiers, and everything else.


Landing Bay

Platform (with exiting section)


Landing Bay

Platform (with exiting section)


Vaccine is the biggest map in SAS 4, and there are many areas you must proceed through, never turning back. The map can be divided into five sections:

  1. The starting area, the landing bay, which seems like an airport (maybe a starport).
  2. The second area, the platform with the train.
  3. The third area, on the train making its course to the lab.
  4. The fourth area, the train station where you'll exit to the labs.
  5. The fifth area, the labs. Includes the laboratory (and the vaccine) and the evacuation site.


  • In the starting section, you can shoot open the door to a room at the top to collect a loot drop.
  • At the plane in the first area, you can go inside to collect a loot drop.
  • Before you go into the train station, there's a loot drop in the right-hand bottom rooms. Both of them contain more zombies, but either one could have the loot drop.
  • In the train station, you can go southeast of the train and go to an inactive train which is seriously infected. There's a loot drop all the way to right in the infested train.
  • In the larger room between lab 1~3 and lab 4~6, you can break into a little room on top of it to get a loot drop.
  • In the top dropship possibility, you can find a loot drop behind a zombie spawning hole.
  • In the left dropship possibility, you can find a loot drop behind a zombie spawning hole.


  • It is very important to have a good mobility as you are working under a time limit. If the player has bad mobility, it is not recommended to collect all the loot.
    • It's also recommended to avoid using armor parts with high movement penalty (example: Hardplate pieces) to assure mission completion within the time limit.
  • If the boss comes and the players cannot defeat the boss, or if there's not enough time, the player can skip the boss entirely and run around it to the dropship.
  • In multiplayer mode, only one person with the vaccine has to get on the dropship, so if very little time remains, players can choose to grab the vaccine and rush to the dropship, splitting up and running past the boss.
  • Once players are on the dropship, they cannot place turrets, or step down the ship to pick up any loot. It is therefore advised to take all the loot before stepping on the ship, or else you face the chance of saying goodbye to a randomly dropped Nantonium box after you have boarded the jet. Sometimes loot from zombies will drop under the ship, but unfortunately this is inaccessible to acquire without the dropship leaving from its position and without it teleporting you on board.
  • Zombies will not be able to attack any players on the dropship. Players, however, can still shoot from the dropship, throw grenades, and use abilities such as assault team or biocleanse. Players can make use of the minimap to snipe zombies out of their field of view.
  • A hidden room above the switch and the gate can be accessed by shooting the designated area outlined in yellow diagonal stripes. Inside is what appears to be a body, which, when walked close to or over, reveals a note, telling players which lab number contains the vaccine. Each room in the lab is numbered one through six on the floor in front of each doorway. By knowing which lab to go to, players don't have to check every single other lab to find the vaccine, saving a substantial amount of time.

Notes on different parts of the map:

  1. Terminal: Runners spawn when you grab the loot on the plane. Therefore, it is advised to send someone to initiate the runner spawn while having the rest of the team outside the plane to deal with them. This is especially important in a Nightmare Match, when the lack of space to run in the plane and highly resistant zombies are much more damaging
  2. Subway station:
    1. There are lots of zombies outside the toilets, but are generally weak. Blind firing will kill a lot, if not all, of them.
    2. When pushing the box out of the way, it's actually easier to let the zombies push the box, since they have greater numbers.
    3. There is a loot in the heavily infected southern train. You may or may not aim for it, as it is a rather risky place with a lot of zombies down there. It is especially not advised to get that loot in Nightmare Match.
      1. But don't rush into the northern train and yell at your team to hurry up. You're better off supporting them even if you don't want the loot. If you do, don't stay behind to kill all the zombies. Remember, this is a timed mission. You need to grab the vaccine, not kill the zombies. Besides, tasty loot lies in wait later. It is essential that you do not die here, or your respawn time will greatly delay your team.
  3. Vaccine compound:
    1. A small but useful feature for lower level players here, amazingly, is the desk outside the door. There is a small gap behind the desk that allows you to lead the zombies in a circle, buying your team time to rush and unlock the door, as well as time to reload your weapons.
  4. Terminal 2 part 2: This is where the boss comes in. The boss zone is huge, so there is less to worry. If time is sufficient, you may go "treasure hunting". There is loot on the topmost and lowest plane spawn point. If you're in bad condition or time is limited, run to the plane. You can avoid the boss if you want.
  5. Others: Alternatively, you may head straight for the boss area. Once you pass a certain point, all zombies in Terminal 2 part 2 appear as well as the boss. After you finish off the boss, you can head into the lab easily, as the zombies in the terminal area will hit the max spawn limit and no zombies can spawn in the lab. This does not work in Nightmare Mode.

Zombie Assault 4 (SAS4) Mission 2 - Vaccine (Part 1 of 2)

A level 39's walk through of Vaccine. (Part 1 of 2)


Zombie Assault 4 (SAS4) Mission 2 - Vaccine (Part 2 of 2)

A level 39's walk through of Vaccine. (Part 2 of 2)

Map Specific Achievements


The pilot's seventh dialogue

  • There are a total of six different dialogues the pilot has, with some being situation-dependent.
    • One such example is if you collect the vaccine before the 5:00 mark, the "Get focused, soldier, you only have a few minutes to find that vaccine" dialogue will not appear.
    • There was apparently a seventh dialogue, however it appears to have been removed. In a CSV file located in the mobile version's game file, the message can be found, and reads "Get on the damn ship! I'm not waiting around!" It is located between the "You have 60 seconds before operation Disinfect commences." and the "I have to go... I'm sorry..." message.
  • This is the only map in SAS 4 with multiple zones.
  • If a player calls in an Assault Team in the final area (before the vaccine is collected) and moves back to the subway, the Assault Team will sometimes actually move to the laboratory.
  • According to the intro, the team arrive at the spaceport forty minutes after the activation of the Jolt ship. However, while Griffin and Combot's conversation implies that the weapon commences its attack an hour after activation, players only have a maximum of fourteen minutes to retrieve the vaccine.
  • In mobile multiplayer version, players have to be careful not to get left out too far from the most advanced team member in progress nor progressing too fast, especially before arriving at the lab progress points.
  • If the progress reached the point where the subway station is cleared or when the system text dialog "The northern train will take you to the lab" appears, any party member still in the terminal area before the first entrance gate will have to wait until 8 minute time left mark because the gate is re-closed and will only re-open on 8 minute mark.
  • If the subway station is cleared and majority of the party (2 out of 3, or 3 out of 4) has already boarded the northern train, the game usually will attempt to teleport the single member left outside into the train. This is especially so if they are dead. However, if the member is still in the terminal area, there is a chance it will teleport the player out of the map and can't move, forcing the player to quit.
  • A glitch can happen where the game can trap all but one player. If someone is just on the edge of a subway's door as all other players enter through it, the next area will load and the player on the edge will be outside of the subway. If the outside player stays close to the other players the game will progress normally, however if they choose to go ontop and to the right of the subway they will load into the next area on the stairs going up to the street, trapping the other players by freezing the subway sequence. (This has only been confirmed on mobile)
  • In the mobile version of the game, the dumpster which blocks the stairs in the first area of the map was previously there, but was then removed in a patch update. (Unsure if this removal occured on the PC version as well.)
  • Vaccine is the only mission where you don't have to kill the boss to complete the mission. Running to the drop ship (provided you have the vaccine) will complete the mission, but you do sacrifice any loot dropped from the boss, but does save you from losing any other strongboxes you already collected.
  • If at least 1 player has entered the ship with the vaccine in a multiplayer game when the timer has nearly expired, the other players can stay out to kill the boss(es) if so desired.
  • On the last part of the mobile version's intro cutscene to the mission, the pilot's rendition appears to be more polished, including a transparent red visor.
  • If the mission starts in singleplayer, you have 9:30 minutes to finish the mission. If started in regular multiplayer, the clock gains an extra minute, and in Nightmare Mode the clock starts at 11:30.

The outcome of a failed Vaccine mission.

SAS: Zombie Assault 4 Missions
Onslaught · Vaccine · Survivors · Zombie Pods · VIP · Power Out · Last Stand · Ice Station · Meltdown