Zain targeted the Spitter because he knew killing this second-stage mutated zombie would end their biggest concern. After that, the group would get out of the supermarket, find the lorry and escape somewhere, but the situation took an unexpected turn.
For a moment, Zain hoped that the red liquid wouldn't work. With the Spitter zombie dead, maybe it couldn't control them, but it didn't take long for Zain to know that it had worked because he could sense it.
When the red liquid landed on the floor, it didn't react, but now that it was on Skittle, Zain could sense an aroma and felt a strong urge to walk towards it. For Zain, it was easy to hold back, but for all the other zombies, who could no longer use their brains properly, they were unable to.
They had already stopped focusing on the entire group as all the zombies in the area headed towards Skittle. Since Mark opened the store shutters a while ago, over a hundred zombies were already inside.