Magento: Disable flat catalog product on the fly

disable_flat_catalog_product.php

<?php
/** @var Mage_Catalog_Helper_Product_Flat $helper */
$process = Mage::helper('catalog/product_flat')->getProcess();
$status = $process->getStatus();
$process->setStatus(Mage_Index_Model_Process::STATUS_RUNNING);

/** @var $collection Mage_Catalog_Model_Resource_Product_Collection */
$collection = Mage::getResourceModel('catalog/product_collection'); // Use EAV tables
// ... custom stuff

$process->setStatus($status);