[RESOLVED] Why won't poison kill my party?

As the title says , my party won't die when poisoned even when there HP = 0 they won't die. (My poison can make HP 0 , not 1 as the basic configuration)
tried in battle = they die
tried in battle + poison = they die
On map (event HP -9999)= They die
On map + poison + event HP -9999 = They die
On map + poison = Won't die

EDIT: answer in script request section