How to make script run only if it touches a specific block?

You might be better off using a module which would handle additional code.

Example module:-

local run = false

local function runCode()
    while run do
        -- code
        wait(0.5) -- need a wait in the loop
    end
end

local function stop()
    run = false
end 

return function()
    if run then return end --  no need to run twice
    run = true

    spawn(runCode) -- create a new thread for run
    delay(5.3, stop) -- delay the stop function for 5.3 seconds
end

script:-

-- load module
local run = require([location to module]) -- module passes back a function

script.Parent.Touched:Connect(function(hit)
    run() -- run out code
    -- additional code can be run as we created a thread so this code will not yield
end)

Enabling and disabling scripts is a bad idea as you have no control over how they stop. Using a module should help you a lot in this case. Modules are very usefull but will take time to learn if you have not used them before.

I hope this helps, please comment if you do not understand any parts of the code.