Why doesn't my else statement run when my if statement isn't fullfilled?

local Door = script.Parent

function onTouch(Brick)
	local Player = Brick.Parent:findFirstChild("Humanoid")
	if(Player ~= nil) then
		local TShirt = Player.Parent:findFirstChild("Shirt Graphic")
		if TShirt.Graphic == "http://www.roblox.com/asset/?version=1&id=1028594" then
			Door.CanCollide = false
			Door.Transparency = 0.5
			Door.BrickColor = BrickColor:Random()
			wait(2)
			Door.CanCollide = true
			Door.Transparency = 0
			Door.BrickColor = BrickColor:Random()
		else Player.Health = 0
		end
	end
end

Door.Touched:Connect(onTouch)

So my code checks if the player has this exact t shirt and if the player has it will make the player able to pass through a door. This works. However when a player doesnt have the exact t shirt it is meant to kill the player. This doesnt work. So when i walk into the door without the t shirt it just says "Workspace.Part.Script:7: attempt to index nil with 'Graphic'" can anyone help with making my else statement run?

else Player.Humanoid.Health = 0