When I change just the x value with the vector 3 the part randomly is placed higher ?

local module = {}

NPCs = script.Parent:WaitForChild("Aliens")
End = script.Parent:WaitForChild("EndPart")
Sweeper = script.Parent:WaitForChild("Sweeper")

function module.mainActivate()
 if NPCs and End then
local move = coroutine.wrap(function()
  while true do
   wait()
   Sweeper.Position = Sweeper.Position + Vector3.new(1,0,0)
   NPCs.Alien1.Humanoid:MoveTo(End.Position)
   NPCs.Alien2.Humanoid:MoveTo(End.Position)
   NPCs.Alien3.Humanoid:MoveTo(End.Position)
   NPCs.Alien4.Humanoid:MoveTo(End.Position)
   NPCs.Alien5.Humanoid:MoveTo(End.Position)
   NPCs.Alien6.Humanoid:MoveTo(End.Position)
   NPCs.Alien7.Humanoid:MoveTo(End.Position)
   NPCs.Alien8.Humanoid:MoveTo(End.Position)
  end
 end)
 move()
  end
end

return module