Can someone help me fix this script, Im trying to make a SurfaceGUI control a global alarm system?

This is for a Star Trek themed Alert system

d=script.Parent

if     _G.BlueAlertactval.Value == true then

for i = 1, 10 do
      d.BrickColor = BrickColor.new"Really blue"
      d.PointLight1.Enabled = true
      d.PointLight2.Enabled = false
      d.PointLight3.Enabled = false
      d.PointLight4.Enabled = false
      d.RedAlert:Stop()
      d.YellowAlert:Stop()
      d.BlueAlert:Play()
      d.IntruderAlert:Stop()
end
elseif
    _G.BlueAlertactval.Value == false then
    for i = 1, 10 do
    d.BrickColor = BrickColor.new"Medium stone grey"
      d.PointLight1.Enabled = false
      d.PointLight2.Enabled = false
      d.PointLight3.Enabled = false
      d.PointLight4.Enabled = false
      d.RedAlert:Stop()
      d.YellowAlert:Stop()
      d.BlueAlert:Stop()
      d.IntruderAlert:Stop()
end
end