How would I make a different script function upon standing on a brick?

You can do this all in one script actually! You just need to call the touched event on the part you stand on and then run the your door opening code.

local part = script.Parent -- Part to step on
local door = game.Workspace.Part2 -- Door

local open = false

part.Touched:connect(function(hit)
	if hit:findFirstChild('Humanoid') and hit:findFirstChild('Torso') then
		if not open then
			for i = 1, 29 do
				door.CFrame = Door.CFrame + Vector3.new(0, 0, 0.5)
				wait(0.02)
			end
		end
	end
end)

You might also want to add some door closing code using the TouchEnded event aswell.