For loop won't work with my button door. Need it for a multistage rocket?

Help.

script.Parent.MouseClick:connect(function()
	if script.Parent.Parent.Parent.DOOR.Transparency == 0 then
	for i = 0, 1, 0.1 do
	script.Parent.Parent.Parent.DOOR.Transparency = i
	wait(.01)
	end
	script.Parent.Parent.Parent.DOOR.CanCollide = false
	elseif script.Parent.Parent.Parent.DOOR.Transparency == 1 then
	for i = 1, 0, -0.1 do
	script.Parent.Parent.Parent.DOOR.Transparency = i
	wait(.01)
	end
	script.Parent.Parent.Parent.DOOR.CanCollide = true
	else
	script.Parent.Parent.BrickColor = BrickColor.new("Really red")
	wait(.1)
	script.Parent.Parent.BrickColor = BrickColor.new("Toothpaste")
	end
end)

I'm making a multistage rocket but I need a way for the astronauts to get in. I decided to make a button door rather than setting a brick's cancollide property to false. I want it to fade in and out. I've tried with for loops and it isn't working.

It opens and closes once but doesn't ever again.