Lin Qiao didn't leave right after she turned invisible. Instead, she stayed around those people and zombies to observe them. They had stopped talking about that robber, and started talking about her.
She guessed that these people and zombies would come back someday. She didn't mind it anyway. Judging by the two human beings' attitude toward their zombie friends, zombies were treated equally in their base.
Also, those zombies didn't seem to be under control. Their minds were all clear, and they followed the two human beings willingly.
But still, Lin Qiao sensed something special from those zombies' minds. Their base might have used some scientific technology to keep their memories and clear minds.
That was a mysterious base indeed.
She watched them leave, and didn't think too deeply about the fact that they might come back in the future. If they came back, she would like to cooperate with them anyway.