HOw do I make this timer for everyone in the server?

I've been making a script for a timer and I got the basics down. It countdowns and switches team. My problem is it just switches the team and restarts the time how would I fix this?

while true do
	wait(1)
	if script.Parent.Value == 290 then
		script.Parent.Parent.Parent.Parent.Parent.TeamColor = BrickColor.new("Crimson")
		script.Parent.Parent.Parent.Parent.Parent.Character.Humanoid.Health = 0
	else if script.Parent.Value == 0 then
		script.Parent.Parent.Parent.Parent.Parent.TeamColor = BrickColor.new("Medium Stone grey")
		script.Parent.Parent.Parent.Parent.Parent.Character.Humanoid.Health = 0
	else
		script.Parent.Value = script.Parent.Value - 1
		end
	end
end

I think that might be what you're looking for?

while wait(1) do
    if script.Parent.Value == 290 then
        script.Parent.Parent.Parent.Parent.Parent.TeamColor = BrickColor.new("Crimson")
        script.Parent.Parent.Parent.Parent.Parent.Character.Humanoid.Health = 0
    elseif script.Parent.Value == 0 then
        script.Parent.Parent.Parent.Parent.Parent.TeamColor = BrickColor.new("Medium Stone grey")
        script.Parent.Parent.Parent.Parent.Parent.Character.Humanoid.Health = 0
	end
        script.Parent.Value = script.Parent.Value - 1
    end
end