Why are they dieing?

Looks

Firstly, I am going to code block your code and make it readable.

local civN = script.CivilianN.Value 
while civN > 0 do 
    civN = civN - 1 
    person = game.Lighting.People.Civilian:Clone() 
    person:MakeJoints() 
    person.Parent = game.Workspace 
end

The problem

You are making their joints before they have made it into workspace

Here is a fixed version

local civN = script.CivilianN.Value 
while civN > 0 do 
    civN = civN - 1 
    person = game.Lighting.People.Civilian:Clone() 
    person.Parent = game.Workspace 
    person:MakeJoints()     
end

I hope this helped you