Vaccine



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

Plot
After finding no signs of life other than zombies on Planet Thera, the destruction of the infested planet by an orbital strike satellite is verified in defense of the future to mankind.

However, a zombie outbreak has occurred on Planet Aartis, where the human race resides. At the same time, a vaccine has been found in a laboratory on Planet Thera by the Combot, vital to the survival of humans. The destruction of Thera cannot be taken back 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, the devasation of the planet, destroying the vaccine and the soldiers.

Layout
It is the biggest map in SAS4, and there are many areas you must proceed through, never turning back. The map can be divided into five sections:
 * 1) The starting area, which seems like an airport (maybe a starport).
 * 2) The second area, the train station.
 * 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 outside.
 * 5) The fifth area, the outside. Includes the laboratory (and the vaccine) and the evacuation site.

Loots

 * 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. (You must enter both rooms for the loot to spawn)
 * 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.

Tactics
It is very important to have a good mobility. Assault class has the highest possibility of completing the mission because of its fast but effective melee attacks and its mobile assault team. If the player has bad mobility, it is not recommended to collect all the loot.

Once the boss comes and the player it too weak to defeat the boss, or if there's not enough time (<30 seconds), the player can kite the boss out of the small passageway and run around it to the dropship without having to kill the boss.

It is recommended to ignore all the zombies if the player can since there's too many and it will take too much time. At earlier levels though, when the time limit is greater than twelve minutes or so, the zombies will be very weak and all of them can be killed within the time limit.

In multiplayer mode, only one person has to get on the dropship, so if very little time remains, all players grab the vaccine and rush to the dropship, splitting up and running past the boss. In a four-player game, three players at most can die in sacrifice, while the last alive player can rush to the dropship. It doesn't matter if all players are on the dropship or not, just if at least one person who grabbed the vaccine boards the dropship.

Once players are on the dropship, they cannot place turrets, use their skills or step down the ship to pick up any loot. Zombies will not be able to attack any players on the dropship. Players can still shoot from the dropship and throw grenades. This makes it helpful for any players struggling to get on the ship. It may be a good idea to take out the nearby zombies while on the dropship to clear the way for other players and to shoot the zombies chasing the other players (if the player is in range).

If little time remains and the lab doors haven't been opened yet, 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. Be careful not to open any other lab doors, or else different types of zombies will appear inside the room,then rushing you.

Notes on different parts of the map:
1) Terminal: Easy peasy as long as your gun has pierce. Best if you are using a shockfield or stripper. Just rush in and blast what you can see. Once your gun runs out, circle around the zombies, making them cluster together, then finish them off. The upper loot isn't special, but watch out for the one in the plane. You don't want to be caught in there when the runners spawn

2) Subway station: This is one of the hard parts. What i usually do is that i blast what i can see, then rush through the two conveyor belts. Once you get to the other side, you can attack the zombies on both sides with your team, which is easier.

Alternatively, you can just forget about that area and rush forward to the hallway next to the toilets where there is a LOT of zombies and leave the ones before to your team. These zombies are generally weak. Blind firing will kill a lot of them. Be sure to check the toilets for loot.

When pushing the box out of the way, it's MUCH easier to actually let the zombies push the box, since they are in a great mass. After they reveal the passage, rush in but don't cross yet. At this position, you can shoot at the ROW of zombies, which means more of them are exposed (if you're using a shotgun)

Onwards next to the platform. 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 many strong zombies down there. If your team manages to get in there before you and it's not a box, i would recommend leaving it.

But still, don't rush into the northern train and yell at your team to "come on!!!". You're better off supporting them even if you don't want the loot. If you do grab the loot, don't stay behind to kill all the zombies. 'FOCUS ON THE OBJECTIVE!!! PLEASE!!!' You need to grab the vaccine, not kill the zombies. Besides, tasty loot lies in wait later. Rush to the northern train. It is essential that you do NOT die here. Even if you're burning and poisoned, struggle onto the train. You can die there

3) Train: Easy peasy, just watch out for acidic puddles. I've been killed by those more than zombies. I would recommend sticking to the leftmost and rightmost side, instead of lingering in the middle, where you are the main focus of the zombies from 2 to 4 doors.

4) 2nd terminal part 1: If you are A) a very offensive player or B) a very strong player who is willing to bear a burden or C) a very strong and offensive player, i would recommend brushing past the shielders right into the terminal. As the first food that comes across, all the zombies will target you. Simply throw nades or summon assault team and clear them all, allowing your team to get to the vaccine room easily. Here, you MUST kill them ALL. You don't want your back being attacked when you are getting the vaccine. If someone else is doing that job, rush to the vaccine. Again, FOCUS ON OBJECTIVE!

5) Vaccine compound: Quite a difficult part. There are mainly 2 things to do here. A) Blast the Upper wall to reveal the toilet and the vaccine's location and B) Open up the lower room. I would recommend killing the zombies on the upper part first. Really, you don't want zombies breathing down your front as well as your back.

A small but VERY important feature here, amazingly, is the desk outside the door. When you get here, your health is hardly full, and the bloaters and shielders can swarm you. However, 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. I find this desk VERY useful, it's saved me many times.

Onward inside, when you find out the vaccine number, go STRAIGHT for it. Again, you don't need to kill everyone. If it's 1/2/3, congratz. Just get the vaccine and go. You can proceed to grab the loot (it's hidden in a small locker, couple of shots will reveal it) and health pack, or simply go.

If it's 4/5/6, I would recommend unlocking lab 2, because most of the time when you try to avoid unlocking all three labs, straying in the middle will usually result in unlcoking all three labs. Better to unlock one, then stick to one side. Remember, NO NEED TO KILL EVERYTHING!

6) Terminal 2 part 2: This is where the boss comes in. Deploy what extra turrets you have. The boss zone is ginormous, so nothing to say of it. If time is sufficient, you can 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.

Trivia

 * This is the only map in SAS 4 with multiple separate zones.
 * If a player calls in an SAS 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.